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THE PREVENTION OF DENTAL 
CARIES. 





Typical models of child's mouth, aged lo, brought up in 
accordance with the principles advocated, without resort to any 
artificial aids to keep the teeth and gums clean, healthy, and free 
from any trace of caries. 

The right side (the left on this page) of each model was dipped 
into carmine, let dry, then brushed. This was repeated twice. 
The photographs indicate how imperfectly the crevices and inter- 
dental spaces of teeth are cleaned. Incidentally it may be noted 
that the models show a particularly perfect set of teeth without 
crowding and consequently relatively easy to clean. The child, 
one of the 14 referred to, page 51, having been brought up on food 
requiring mastication, has worn the cusps especially of the tem- 
porary teeth, so that the crevices are relatively easily brushed. 



The Prevention of 
Dental Caries 



By 



J. SIM WALLACE, D.Sc, M.D., L.D.S. 

Dental Surgeon and Lecturer on Dental Surgery and Pathology, 
London Hospital. 

Hon. Dental Surgeon to the West End Hospital for Nervous 
Diseases. 



SECOND EDITION, 



London : 

Published at the Office of (tbC BCUtal IRCCOrl), 

Alston House, Newman Street, W. 

1912. 



(5 



C/ 



nj 



KK331 



PREFACE to the Second Edition 

The first edition of this little book has been received 
most generously by the medical and dental press. 
One journal {The Medical Magazine) gave up some 
forty pages to an almost complete reproduction of its 
contents. Another (The Hospital) devoted three 
successive articles to an exposition of the principles 
therein advanced. Others accorded to it a leading 
article or a lengthy review, and more or less vigorously 
indicated the necessity for all medical men to become 
conversant with its contents. There is consequently 
but little wonder that the first edition was sold out 
within six months of its pubHcation, and no apology 
seems necessary for having it reprinted. 

J. SIM WALLACE. 

150, Harley Street, London, W. 
Jan. 10, 1912. 



1G4 



CONTENTS, 



INTRODUCTION 



Page 
I 



I. The Prevention of Conditions which Pre- 
dispose TO Dental Caries . , . 7 

Hypoplasia ..... 8 

Irregularities of the Teeth . . 9 

Recession of the Gums , . . 15 

11. Mucus and Saliva in the Prevention of 

Dental Caries . , . . . 18 

III. Prevention of Certain Dietetic Habits 

which tend to induce Dental Caries 22 

IV. The Prevention of the Exciting Causes of 

Caries ....... 25 

V. The Normal Self-cleansing Processes. . 31 

VI. Diet in Infancy and Childhood . . 37 

»^ 

Vll. Reasons for Insisting on the Natural 
Hygienic Method of Preventing Dental 
Caries ..... . . 43. 

VIII, Artificial Methods of Preventing Dental 

Caries — 

Mouthwashes . . . . 53:. 

Antiseptics . • . . . 54 

Toothbrush - - - ■ • 55 

Toothpowder ..... 59' 

IX. On Disseminating Knowledge Necessary for 

the Prevention of Dental Caries . 63 

Bibliography ....... 68 

viii. 



THE PREVENTION OF DENTAL 
CARIES. 



INTRODUCTION 

Dental Caries is one of the most easily and certainly 
preventable of diseases, and there would seem now 
to be no valid excuse for the bringing up of children 
with decayed teeth, together with all the pathological 
results which they give rise to. Unfortunately, so 
far it is only those who have become interested in the 
subject, and who are themselves possessed of the 
required knowledge to come to correct conclusions 
on the subject, who know the simple secrets of pre- 
vention. That is to say, a goodly proportion of the 
dental profession and here and there a few medical 
men who have paid attention to the long and laborious 
investigations which have led to the solution of this 
important problem. It is with the idea of letting what 
is already known to a few become more widely known, 
among medical men more especially, that I venture to 
publish this pamphlet. Those who find the subject 
of interest or importance would do well to make their 
knowledge more secure, by acquainting themselves 
not only with the outlines of the means of preventing 
the disease as presented in these pages, but also with 
at least a general knowledge of the pathology and the 
etiology of the disease, because for some considerable 
time, incredulity, ignorance, prejudice, vested interests 
and the commercial spirit are likely to continue to 
make a stubborn resistance to the diffusion of the truth. 



2 INTRODUCTION 

It would be a great service to mankind if a goodly 
number of medical men would become thoroughly 
acquainted with the subject so as to rid the land of 
ideas which are now definitely known to be wrong, 
and indeed often actually markedly instrumental in 
causing the disease. Medical men and physiologists 
engaged in teaching medical students should certainly 
make sure that it is not their precepts which are largely 
responsible for the widespread prevalence of the disease. 
Those who would like to supplement their knowledge 
may be recommended to consult the more recent 
standard text-books, e.g., J. F. Colyer's " Dental 
Surgery and Pathology," or the larger " System of 
Dental Surgery," edited by Mr. Norman Bennett, 
about to be published by the Oxford Medical Press. 
Therein they will find the groundwork of the subject 
sufficiently thoroughly treated to let them master all 
important points. The references at the end of this 
pamphlet will also help anyone with regard to any 
special point on which he may desire to have further 
information. 

It would be difficult for me to speak too strongly on 
the great importance of the study of this subject at 
the present time ; not only because dental caries is 
such a general, and in its ultimate results so frequently 
such a fearful scourge, but also because there has been 
such an extraordinary change during the last few years 
in the conceptions of the dental profession with regard 
to the cause and the prevention of the disease. For- 
merly, the cause was vaguely supposed to be hereditary, 
constitutional, intangible and irremediable ; now it 
is definitely known to be simple, definite, tangible 
and remediable. Correspondingly from the most 
doleful pessimism the profession has passed into a 
most optimistic attitude. Instead of listening to papers 
on " The Teeth as the Beginning of the End of the 
Civilized Race," we now hear of " the decimation of the 
ranks of the dentists which will follow when once the 
eyes of the pubhc are opened to this scourge and its 



INTRODUCTION 3 

possibilities of prevention." And " that we look 
forward with every belief in the ultimate conquest of 
the disease. We see a future people free of it, and 
marvelling that those of to-day could have suffered 
so long and so patiently. We imagine them asking 
themselves what strange perversity could have filled 
the mind of people who were wilHng to spend thousands, 
nay, millions, of pounds a year on the cure of a disease, 
upon discovering the cause of which they would not 
spend a penny. Can we wonder at them if they think 
thus ? For everywhere we see signs of this dreadful 
malady ; it ruins the beauty of many, it enfeebles 
those who would be otherwise healthy, it helps to fill the 
workhouses and poor infirmaries with preventible 
sickness, it is the direct and indirect cause of a waste of 
fabulous sums of money." 

From multitudinous researches which seemed to 
bring us no nearer to the practical solution of the 
problem of dental caries, we have come to hear that 
caries is essentially a preventable disease. From a 
feeling of shame that the dental profession were unable 
to solve the problem of prevention it is now said that 
by having done so we have " ennobled the avocation 
of the dentist in the medical and scientific world." 
Instead of anticipating the continued increase of 
dental caries, we confidently anticipate its more or 
less complete extinction. And for those who dread 
their annual visit to the dentist we can give the most 
satisfactory assurance that this, though it may con- 
tinue to be expedient, will be but rarely necessary. 
Moreover, we can say that we are on the eve of a more 
or less systematic crusade. A crusade, no doubt, 
initiated by us in establishing rational methods for the 
prevention of caries, but now about to be passed on to 
those whose position and authority fits them in some 
ways more satisfactorily for carrymg home the truth 
to the mass of the population. Thus, Dr. James 
Wheatley (Medical Officer of Health for Shropshire) 
has set Medical Officers of Health an excellent example. 



4 INTRODUCTION 

After studying the subject for himself he brought 
it forcibly before the medical profession in his branch. 
He then lectured to the school teachers in his neigh- 
bourhood, and finally prepared leaflets for the instruc- 
tion of the parents of the school children in his county. 
Like many others who have studied the subject, he 
came to appreciate its enormous importance not only 
from the point of view of the teeth, but also from the 
point of view of health in general. Thus, like others 
who have troubled to study the subject, he re-echoed 
the sentiments of those who feel that the principles 
of dietetics suggested by a study of the food in relation 
to the teeth, will yet be found to give rise to the greatest 
triumph over disease that has as yet been recorded 
in the annals of medicine. I have heard, further, that 
other Medical Officers of Health are about to proceed 
in like manner. We cannot wonder at this ; in fact, 
we could only wonder if other Medical Officers of Health 
did not do so, because the principles are so well estab- 
lished, and there is no other method known which would 
have any appreciable effect m preventing the disease. 
Moreover, the method costs nothing ; and, indeed, if 
a considerable tax were put on sugar a large amount 
of revenue would be derived, while a corresponding 
amount of good would follow. 

It would seem from many considerations, besides 
those to which attention is directed in the following 
pages, that the most important principle in dietetics 
will prove to be that which claims that the diets which 
are recommended should be such as will leave the 
different parts of the ahmentary canal in a healthy or 
hygienic state. When once it is pointed out, this 
appears so obviously the first and most necessary 
consideration that it would seem incredible that it 
should continue to be overlooked in the future. The 
amount of nutrition, or the digestibility, or the absorb- 
ability, or the number of " calories " which may be 
derived from an article of diet, should always be pre- 
ceded by the consideration whether it leaves the mouth 



INTRODUCTION 5 

and alimentary canal in a healthy or hygienic state. 
Yet it is obvious that in the past this consideration 
has been entirely overlooked ; and it would be difficult, 
if not impossible, to find a well-known writer on dietetics 
(except Dr. Harry Campbell) who has paid sufficient 
attention to the subject to be able to give any idea 
whether the articles of diet which he may be recom- 
mending are calculated to ruin the dental armamen- 
tarium or keep it in a hygienic state. Similarly the 
treatment of diseases resulting from the frightful state 
that the mouth and teeth get into as the result of 
unhygienic methods of feeding without knowing how 
to alter those unhygienic habits, is peculiarly unscien- 
tific, and, instead of curing the trouble, has led in the 
past to an untold amount of chronic ill-health. 



Chapter I 



PREVENTION OF PREDISPOSING CAUSES 

Uncertaikty may still exist with regard to the reasons 
why the teeth in certain mouths fall a prey to caries 
while in others they do not, but the pathology of the 
disease and the nature of the immediate or exciting 
cause is definitely and accurately known, and 
fortunately beyond the Hmits of controversy. It is 
now universally admitted that dental caries results 
directly from the fermentation of carbohydrates in 
the crevices of, or between teeth, or more generally in 
such situations as carbohydrates are liable to lodge 
unduly and permit of fermentation. The facts upon 
which this generaHzation is based are of so great 
importance from the point of view of prevention that 
a few words on causation may at the outset be desirable. 
Various conditions, such as warmth, moisture and the 
presence of bacteria, do not require to be discussed at 
present. These conditions are so constant they hardly 
need be more than referred to. The variable condition 
or antecedent, which when present caries inevitably 
follows, and which when absent caries cannot take 
place, must be more fully noted. This antecedent 
or condition is the undue lodgment or stagnation of 
fermentable carbohydrates in more or less immediate 
contact with the teeth and undisturbed by the free 
access of saliva. This being so, what must be 
considered is how the undue lodgment of carbohydrates 
may be prevented. It is obvious that the teeth them- 
selves may be of a shape such as ^\dll predispose to the 
lodgment of carbohydrates, or they may be so arranged 



8 PREDISPOSING CAUSES 

as to predispose to undue retention of viscous and 
fermentable food-stuffs, or their relation to surrounding 
parts (gums) may be such as to predispose to stagnation. 
In other words, the predisposing causes of caries are 
abnormal pits and crevices, irregularities of the teeth, 
recession of the gums and abnormal relations of the 
gums, more especially round the wisdom teeth. 
Practically all these predisposing causes may easily 
be prevented. All the predisposing causes have their 
importance and each will be considered separately. 



THE PREVENTION OF DEVELOPMENTAL DEFECTS IN THE 
TEETH (hypoplasia) 

It is generally recognized that the pits and grooves 
(hypoplasia) which result from the defective formation 
of the enamel are caused by disease during its forma- 
tion. Measles and scarlet fever are said to be the 
diseases most commonly giving rise to such defects ; 
but other severe constitutional diseases may produce 
similar results. It is, of course, obvious that such 
diseases should, if possible, be prevented and the 
general hygienic precautions against them should be 
taken. In addition to what may be called the recog- 
nized methods of preventing such diseases it should be 
observed that a dirty mouth is always dangerous to 
the health of young children, and it is doubly objection- 
able should such infectious diseases also be contracted. 
It happens that at the age (1-3 years) when the teeth 
susceptible to hypoplasia are being formed, the food is 
most frequently presented to children in a soft or 
pappy form, which has little or no detergent effect on 
the teeth and, moreover, during these years the tem- 
porary teeth are seldom brushed sufficiently to keep 
them clean. It thus happens that these infectious 
diseases may be made more severe and prolonged or 
complicated by the insanitary state of the mouth and 
the consequent pollution of what food the child may 



PREDISPOSING CAUSES 9 

take. As the fact of a child having measles or scarlet 
fever during the formation of the enamel (of the sus- 
ceptible teeth) does not necessarily result in hypoplasia, 
it is possible that the keeping of the mouth clean may 
sometimes be sufficient to prevent hypoplasia should 
unfortunately the infectious disease take place at such 
time. It would indeed appear that the malnutrition 
— which may sometimes be prolonged and severe — 
resulting from an unhygienic state of the mouth and 
alimentary canal may in itself be the cause of many 
eases of hypoplasia ; for perhaps the most common 
reply to questions with regard to any particular child 
which shows hypoplasia in later life is that it was very 
delicate — possibly rachitic — and subject to severe 
indigestion during childliood. Defective development 
of the enamel has also been attributed to the bottle- 
feeding of infants. When this is not carefully carried 
out, especially with regard to sterilization of the milk, 
disease and malnutrition are likely to supervene, and 
it is further noteworthy to find that hypoplasia is more 
common among the children of the poor than of the 
well-to-do .35 This may be presumed to indicate that 
the less hygienic the surroundings the more Likely 
is the disease to occur. To sum up it may be said that 
in addition to ordinary hygienic precautions and breast- 
feeding, it seems probable that hjrpoplasia might largely 
be prevented by keeping the mouth clean. (The 
methods of doing this will be referred to subsequently.) 



THE PREVENTION OF THE IRREGULARITIES OF THE 

TEETH 

Abnormalities in the position of the teeth are much 
more important as predisposing causes of caries than 
the abnormalities in form which have just been con- 
sidered. WTiile hjrpoplasia, according to statistics 
compiled by Mr. Sidney Spokes,35 is present in from 
4*6 per cent, to 7-1 per cent, of the permanent teeth 



10 



PREDISPOSING CAUSES 



according to the class examined, irregularities in posi- 
tion such as may predispose to caries no doubt exceed 
80 per cent, among adults in this country ; and fre- 
quently the greater number of the teeth may, to a 
certain extent, be predisposed to caries in this way. 
The predisposition to caries, however, is not by any 
means always in direct proportion to the amount of 
the irregularities. Indeed, certain gross irregularities 
giving rise at places to practically complete stag- 
nation, especially when there is a tendency for 
tartar to be deposited, do not, except in an indirect 
way (to be noted hereafter), predispose to caries. The 
irregularities which most surely induce caries are those 

Be B(lutse.p BY i^C&iftu 










which make the food consumed become lodged or 
impacted between the teeth. Nevertheless it may be 
said in general that " any departure from the normal 
arrangement favours the lodgment and stagnation of 
food," 1 and consequently favours the onset of caries. 
Both abnormal relations of the upper to the lower 
teeth and abnormal relations of neighbouring teeth in 
the same arch are recognized to predispose to caries 
by inducing the stagnation of foods. Certain irregu- 
larities in the molar and premolar regions also tend to 
bruise the enamel and render it liable to rapid decalci- 
fication.25 Thus when the level of the crown of a molar 
is distinctly below the level of its neighbour the 



PREDISPOSING CAUSES ii 

approximal aspect of the higher tooth is almost in- 
variably first and most rapidly attacked by caries, 
the thick rounded cusp of the lower tooth bruising the 
relatively thin enamel of the neighbouring tooth. 
The flat and relatively thin enamel nearer the neck of 
the tooth is readily bruised by the rounded part of the 
molar tooth lying against it when during mastication 
it may be subjected to a pressure occasionally amount- 
ing to more than 120 lbs. 

The means at our disposal for preventing these 
irregularities may briefly be noted. Breast-feeding 
and general hygienic surroundings are important in 
being conducive to the normal development of the 
jaws and in the prevention of crowding of the teeth. 
This might be expected on general principles, but it 
has been statistically proved in an investigation by 
Mr. J. F. Colyer,9a who has shown that breast-fed 
children of the better classes have broader arches than 
breast-fed children of hospital patients. No doubt 
this results from the more hygienic surroundings of the 
higher classes. He shows further that breast-fed have 
broader arches than bottle-fed children. This would 
seem to indicate that the hygienic conditions or the 
nutritive quaHty of the food of the breast-fed children 
is more satisfactory than that of the bottle-fed. That 
it is chiefly due to the insanitary conditions almost 
necessarily associated ^\'ith bottle-feeding is indicated 
by the fact that children hand-fed with bottles with 
rubber tubes (which cannot be properly sterilized) 
have still narrower arches than those who are brought 
up on the more modern, more cleanly and easily 
sterilized teat attached directly to boat-shaped bottles. 
From Mr. Colyer's measurements it may at least be 
inferred that not only is attention to the general 
sanitary surroundings important in the prevention of 
irregularities resulting from crowding but also that the 
more sanitary the feeding apparatus, the better are the 
jaws developed, and the results of his measurements 
seem, to corroborate the generaHzation that the 



12 PREDISPOSING CAUSES 

crowding of the teeth is in general proportionate 
to the ill-health or disease which may have existed 
during the development of the jaws.^^^ 

Another point of some importance is the recognition 
of the early efforts of nature to secure correct anta- 
gonism or occlusion of the teeth. It seems probable 
that the instinct to gnaw more or less continuously 
during the coming into place of the incisor teeth 
indicates that the child should be supplied with a type 
of food which will allow and induce it most effectually 
to secure the correct occlusion of the incisors. In days 
gone past it was the custom to let an infant " cut its. 
teeth " on a crust. It is obvious that gnawing such a 
foodstuff will tend to make the child habitually place 
its lower jaw in such a position that the incisors will 
occlude normally and the development of the jaw 
associated with this position and the effect of the 
tongue in moulding the arch will tend to bring about 
the correct occlusion of the incisors. 47 The correct 
occlusion of the other teeth will almost invariably 
follow as a matter of course. From this time onwards 
food which stimulates efficient mastication develops 
the muscles of mastication, including the tongue, ^3 
and correspondingly stimulates the development of 
the jaws so that crowding of the teeth tends thus to be 
prevented. This has been experimentally proved in 
rabbits by Dr. Laurence Baker, 7 for by filing the teeth 
on one side of the mouth so that mastication could not 
be performed on that side, it was found that the bones 
of the jaw and indeed of the nose and base of the skull 
also, did not grow so perfectly as did the bones on the 
side on which mastication was performed. Similarly 
when from certain causes a child does not masticate 
effectually on one side of its mouth for a few years 
a noticeable difference in the size of the different sides 
of the jaws has been detected. More important than 
this, however, is the fact that chronic ill-health during 
the development of the child tends to prevent the 
normal development of the jaws, and recent observation 



PREDISPOSING CAUSES 13 

seems to show that chronic ill-health and concomi- 
tant emaciation in children is largely, indeed almost 
solely, the result of a system of dietetics which has 
resulted in the foisting on children of all ages foods 
which leave the mouth in a state of chronic fermenta- 
tion. The constant swallo\^'ing of the fermented 
products, and associated bacteria, the diseased state of 
the gums and teeth, the absorption of poisons direct 
and indirect, are now recognized as most fertile sources 
of chronic ill-health. Foods of a firm and fibrous 
nature which stimulate the pleasurable activity of 
efficient mastication tend to keep the mouth and teeth 
clean and healthy. On the other hand, the soft foods 
which children are so generally compelled to consume 
do not clean the mouth, but leave it sticking with 
fermentable carbohydrates which no doubt constitute 
an excellent nursery for pathogenic bacteria, and induce 
a state of chronic fermentation which leads to the pro- 
longed ill-health depicted in the pale and emaciated 
faces with ill-developed jaws and contracted arches of 
teeth so generally seen at the present day. 

It is important also to prevent mouth breathing in 
children, because this is a fertile source of crowding 
of the teeth. To prevent mouth breathing it is neces- 
sary to prevent adenoids and associated pathological 
conditions. Adenoids may easily be prevented, as 
they result directly or indirectly in nine cases out of 
ten from cold and damp air. In the tropics, of course, 
and warm countries generally special precautions are 
hardly necessary, as cold and damp air is seldom 
present and neither are adenoids. In cold and damp 
climates, such as our own, statistics^i seem to prove 
that all that is necessary is to prevent the direct ingress 
of cold and damp air, more especially into children's 
bed-rooms during winter. (Some laryngologists now 
advocate that the door of children's bed-rooms should 
be kept open in cold and damp weather rather than the 
window). 30 To ventilate and warm chiefly by means 
of open fires and, if possible, to avoid damp locahties 



14 PREDISPOSING CAUSES 

and houses. Other conditions should be taken into 
account. Thus, excessive clothing of children leading to 
perspiration and chills, together with constant Uability 
to catarrhal infections, say, at schools, especially 
when over-crowded and ill-ventilated, frequently 
results in adenoids. So too over-clothing and conse- 
quent perspiration at night in cold and damp rooms, 
associated with too little clothing by day, may be 
presumed to have a like effect. 

Subsidiary, though frequent, causes of irregularities, 
such as caries and the extraction or at least injudicious^ 
extraction of teeth, need not now be referred to ; such 
extractions are not necessary when the requisite pre- 
cautions for the prevention of caries are taken. Ta 
sum up, irregularities of the teeth may be prevented by 
bestowing ordinary attention on hygienic surroundings, 
by food which stimulates efficient mastication, and by 
rational ventilation. It may be thought that too little 
consideration has been given to the various steps 
between the actual predisposition brought about by 
the irregularities of the teeth — i.e., the conditions 
favouring the undue lodgment of carbohydrate food — 
and the original remediable antecedent or condition 
which should not have been allowed to be present ; 
but it is presumed that all subsidiary conditions which 
are necessarily correlated with the links briefly sketched 
out are obvious and recognized. Thus, though the chief 
links in the chain between cold and damp air and 
irregularities of the teeth are indicated, mention has 
not been made of the fact that with regard to acute 
naso-pharyngitis, " exposure to cold and damp plays 
the chief exciting role," and that " exposure to cold 
really means lessened resistance of the tissue to germ 
vitality, and germ entrance into the substance of the 
(mucus) membrane,"'i2 that this leads to other catarrhal 
infections, and that the blockage of the nose arrests its 
development (von Ziem), yet the significance of these 
facts cannot be overlooked. Furthermore, although 
it is well recognized that the connecting finks in the 



PREDISPOSING CAUSES 15 

causation might be broken at some particular stage — 
thus adenoids may be removed by operation — yet 
necessary though this is when adenoids are present, 
the ideal method of prevention aims at avoiding the 
necessity for operation — in other words, the prevention 
of adenoids. Similarly when irregularities of the 
teeth are present they ought to be corrected. 



THE PREVENTION OF RECESSION OF THE GUMS 

Recession of the gums is another predisposing factor 
in dental caries which, to a great extent, may be easily 
prevented, for this condition results largely from the 
stagnation of debris about the necks of the teeth. 
How this might be prevented by food of such a 
consistency as would act as a continual natural and 
inoffensive brush for the teeth and gums need hardly be 
referred to. It is recognized that teeth which are 
displaced in such a way as not to receive the natural 
pressure and strain of mastication are peculiarly liable 
to recession of the gums. Nor need the fact be men- 
tioned that teeth which are constantly well used are 
more firmly rooted in the alveolar process, so that they 
do not become prematurely functionless through loosen- 
ing. People who have teeth arranged in such a way 
that they are functionless become " long in the tooth," 
and those who do not put their teeth to the principal 
function for which they are so well adapted Ukewise 
become long in the tooth ; so that the caries which we 
so frequently see in later life between and at the necks 
of the teeth is strongly predisposed to by the habitual 
use of food which does not stimulate efficient mastica- 
tion. We may, indeed, say that after the gums have 
receded this predisposition to caries is the most impor- 
tant factor in its causation, especially when associated 
with irregularities. 

It is the albuminous matter and the mucus, together 
with the salts it contains, lodging about the necks 



i6 PREDISPOSING CAUSES 

of the teeth, which is associated with or may induce 
tartar formation and infections resulting in recession. 
It is, therefore, important to note certain bacteriological 
considerations associated with mucus. It readily 
undergoes acid fermentation, but after a time the acid 
fermentation stops and putrefaction begins. 22 A thin 
film of mucus bathed and miscible with saliva does 
not give rise, however, to such acid fermentation as 
would injure the teeth. If a piece of litmus paper 
be moulded over the gums and teeth it will be observed 
that just at the junction of the gums and teeth the 
reaction indicates slight alkalinity, while the part 
which covers the gums indicates slight acidity. It is 
at these gingival margins that the mucus tends most 
to deposit, and if the deposit of mucus, together 
with the associated bacteria, is thick, the deepest part 
more especially will most certainly have reached the 
stage of alkalinity. Here, however, that is, just at the 
gingival margins, complete stagnation of the mucus 
is not permitted, because there is a continual exuda- 
tion of albuminous corpuscles from the gingival organ, 
and this, together with the exudation of a little serous 
matter, greater no doubt when mastication is vigorous, 
supplies the pabulum for the bacteria which liquefy 
and disintegrate the mucus and albuminous matter, 
thus keeping up a continual flux which normally 
prevents tartar formation. It is possible that these 
so-called salivary corpuscles by possessing chemiotactile 
properties may keep the space between the necks of 
the teeth and the gingival margin free from invading 
bacteria, while as they make their exit from the space 
they may also englobe bacteria and prevent masses of 
bacteria adhering about the necks of the teeth. Of 
course, if carbohydrates preclude the beneficent action 
of the saliva and are continuously lodging on this 
m.ucus and albuminous matter, which always contains 
numerous bacteria, caries may result along, or rather 
at some very slight distance from, the gum margin, 
though of course no physiologically correct diet allows 



PREDISPOSING CAUSES 17 

this to happen. On the other hand, if the food which 
lodges is of an albuminous but non-detergent nature, 
then the mucus may not be sufficiently or frequently 
removed and ultimately may tend to allow of the 
deposit of tartar. As a matter of fact, we know that 
in such situations tartar is most frequently deposited, 
especially is this the case when from any reason 
mastication is more or less in abeyance together with 
the dependent and associated seK-cleansing processes. 
Tartar does, of course, protect the necks of the teeth 
from caries ; but it is an irritant to the gums and leads 
to their recession from the necks of the teeth ; more- 
over, being an irritant it gives rise to a certain amount 
of exudation of albuminous plasma from the inflamed 
parts. This supplies the saprophytic micro-organisms 
with undue supplies of pabulum appropriate for their 
development, and thus further enhances the chances 
of infection of the gums by micro-organisms which 
tend further to destroy the gums. It has been found 
that almost pure cultures {Spirillum Sputigenum) may 
often be made from the bacteria associated with this 
hypersemic state of the gums,23 but it has been noted 
also that in such cases caries is conspicuously absent. 
From this it may be presumed that the micro-organisms 
associated with this condition are but feebly able, 
if at all, to decalcify enamel under such circumstances. 
Such conditions of the gums ultimately, however, 
give rise to recession and consequently to a predis- 
position to caries for the spaces that subsequently 
come between the teeth, become more and more remote 
from the h5^er3emic gum and associated saprophytic 
micro-organisms, and such spaces are more and more 
liable to lodge carbohydrates. It is evident, therefore, 
that in order to control the formation of tartar the 
food must be of such a consistency as will stimulate 
efficient mastication and prevent the stagnation of 
mucus and consequently the undue proliferation of 
bacteria. It is suggestive and notable that all clean 
and healthy mouths contain bacteria, e.g., streptococcus 



i8 PREDISPOSING CAUSES 

hrevis, which is both acid-forming in the presence of all 
fermentable carbohydrates (e.g., sugar, starch, lactose, 
maltose, glucose, dextrin)i5 and liquefying in an albu- 
minous medium. It would seem as if Nature had made 
a virtue of necessity, and being unable to exclude 
micro-organisms from the mouth altogether had turned 
them to good use. It is difficult to imagine a better 
method for the prevention of caries at these places 
where the friction of the food, lips, tongue and cheeks 
cannot thoroughly dislodge adherent mucus, for while 
it provides a slippery and protective coating favouring 
the easy washing away of foodstuffs, the bacteria 
incorporated in the mucus and albuminous matter 
(no doubt normally but slow acid producers) provide 
for the continual liquefaction and removal of the 
adherent mucus itself, together with all accumu- 
lations of debris, whether it be albuminous shreds or 
incipient tartar deposit. When we imagine what state 
the mouth would necessarily get into if there were no 
bacteria to liquefy albuminous foodstuffs, or to disin- 
tegrate the film of mucus and help to dispose of or 
prevent the formation of tartar, we realize that the 
bacteria of the mouth appear to play a useful part as 
scavengers in cleaning it. We recognize how important 
it is that a method should obtain for keeping up a con- 
tinual flux, thus preserving the teeth from destruction 
by acid on the one hand, and from the deposit of tartar on 
the other. Fortunately, both these objectionable results 
may be prevented by similar means, namely, a sufficiency 
of food which will stimulate efficient mastication, 
enough to ensure a fair amount of friction, and polishing 
of the teeth and a corresponding stimulation of the self- 
cleansing processes, to be more fully referred to later. 

MUCUS AND SALIVA IN THE PREVENTION OF DENTAL 

CARIES 

Mucus is important as a lubricant and, mixed with 
saliva, a vehicle for the removal of food particles. It 



MUCUS AND SALIVA 19 

lubricates the mucous membrane and teeth on the one 
hand and the food on the other, thus facihtating the 
passage of the food from one part of the mouth to 
another during mastication, and finally ensuring its 
complete, or practically complete, removal from the 
buccal cavity. The mucus is secreted in amounts 
proportionate to the requirements of the particular 
kinds of foods for this purpose. Likewise the saliva 
facihtates the same physiological processes and the 
quality and quantity secreted is also proportionate 
to the requirements of the food consumed.^i Saliva 
has also a marked effect in preventing acids taken in 
food or developed by bacteria from decalcifying the 
enamel, and this effect seems to be much greater than 
could be accounted for simply by its power of neutral- 
izing the acid. 17 Mucus is freely miscible with saliva, 
so that even if mucus has no similar power in protecting 
the enamel from decalcification it does not hinder such 
beneficent action of the saliva. The variations in the 
amount and quahty of the saliva and mucus corre- 
sponding to the quality of the food consumed appear 
to be common to all, whether " susceptible " or 
" immune " to caries. That this is so is not a subject 
of controversy, but nevertheless the fact that the 
normal physiological processes supply with marvellous 
ingenuity the means of securing the cleanliness of the 
mouth and teeth seems to be most persistently over- 
looked by many who believe that the mouth is clean, 
or otherwise, according to whether it has or has not 
been brushed w4th a toothbrush. 

Many now recognize that food demanding efficient 
mastication prevents caries on the masticating surfaces, 
but seem to doubt whether it has any such effect at 
the necks of the teeth. The following argument was 
recently put before me. It was contended that the 
food got into the crevices at the necks of the teeth after 
meals. It was admitted that it did so under abnormal 
conditions of the gums or if the food was of a sticky 
type. To this it was objected that it always must do 



20 MUCUS AND SALIVA 

so, for if a set of teeth mounted, say, on some substance 
to represent the gums were dipped into Hquid, e.g., 
water, and some coloured material, and then taken out 
again it would be seen that the water and colouring 
matter clung about the gingival margins and between 
the teeth. The reply to this was, of course, that such 
would certainly take place, but as the viscous mucus 
covers the teeth and crevices at the edge of the gums, 
much as the water would, that is to say, it would 
certainly be present between the teeth and at the 
gingival margins, and being adherent to the teeth yet 
slippery to the food, the food does not tend to lodge 
in such crevices. As a matter of fact if a normal 
mouth be examined after a meal not ending with fine, 
" short," specially lodgable foodstuffs it will be seen 
that food does not lodge in such situations. If, further, 
say a child (with normal and regular teeth and healthy 
gums) is given chocolate or toffee, and then the mouth 
is inspected a few minutes later, it will be seen that it is 
the crevices in the masticating surfaces which are 
specially liable to lodge such foods, and not the crevices 
of the gingival margins. Food is crushed down into 
the crevices of the masticating surfaces, and is not 
crushed down into the gingival crevices, but it slips 
past them. In the case of the interdental spaces, 
if any viscous foods or food particles get there, they are 
easily and effectually washed away with the saliva 
which is always passing between, at least if vigorous 
mastication is being performed, and the teeth and 
gums are normal in their relations, which, however, it 
may be remarked, they seldom are in the neighbour- 
hood of the wisdom teeth. 

Before the role of the foodstuffs in the etiology, as 
distinct from the pathology, of caries was recognized, 
that is to say, before it was recognized that the chief 
factor in the causation of caries was the tendency of 
certain carbohydrates to lodge unduly about the teeth 
on the one hand, and that the chief factor in the pre- 
vention of caries was the tendency of certain other 



MUCUS AND SALIVA 21 

foodstuffs to brush fermentable carbohydrates away 
from the teeth, it was most generally assumed that 
teeth decayed in some mouths and not in others, 
because of some unexplained susceptibility or immunity 
existing either in the substance of the tooth or in the 
secretions of the mouth. Dr. Black's investigation 
into " The physical character of the teeth "5 in 
relation to their diseases seemed conclusively to nega- 
tive the assumption that susceptibihty or immunity 
resided in the substance of the tooth, and gave rise 
to the idea that a thorough investigation of the oral 
secretions must reveal the cause of susceptibility and 
immunity. But numerous, and in some cases thorough, 
though the investigations have been, it may certainly 
still be said that we have Httle or no knowledge of any- 
thing existing in the saHva or mucus which can account 
for the susceptibihty to caries which is assumed to 
exist in some mouths. 

Independent of normal variations in the saliva 
resulting from variations in the nature of the food 
and other physiological variations, there are occa- 
sionally abnormal variations in the sahva, and these 
variations do have an effect on the rapidity of the 
carious process no doubt. Thus, for example, diseases 
which eventuate in the arrested flow of saliva have been 
recorded, and diabetes may predispose to caries through 
the sahva containing glycogen. Such diseases should, 
of course, be prevented or controlled. If disappoint- 
ment is felt that we are able to say but Httle ^vith regard 
to the constitutional variations of the sahva and 
mucus as predisposing factors in the causation of caries, 
consolation may be taken from the fact that in England, 
where the role of the foodstuifs in the etiology of caries 
is generally appreciated, the role of the sahva and 
mucus as predisposing factors are correspondingly 
felt to be of little consequence. And we do not now 
beheve such statements as, for example, that " in the 
practical considerations of case as they are presented 
to us when we have the care of families of children, the 



22 DIETETIC HABITS 

hereditary predisposition to caries is of the first 
importance." ^ Yet this was the view which was held 
even by those who denied that the chemical composi- 
tion of the tooth had anything to do with the predis- 
position to caries. Indeed, we now believe that the 
hereditary predisposition to caries resulting from the 
hereditary variations in the oral secretions is to all 
intents and purposes a negligible consideration, for it 
is admitted that what we took for hereditary predis- 
position turns out on more critical examination to have 
been similarity of environment. lo It had not been 
noted in this connection that similar dietetic habits 
ran in families and thus accounted for the apparently 
markedly hereditary nature of the disease. Similarly 
we are inclined to put little importance on the faint 
differences in the alkalinity or acidity of the saliva 
or slight variations in the amount of viscidity of mucus, 
when, notwithstanding such variations, we are able by 
altering the dietetic regime to make anyone practically 
immune to caries. If it be assumed that the dietetic 
regime alters the constitution in such a way that the 
saliva and mucus become healthier, and that in this 
way the change to immunity is brought about, then at 
any rate we have explained the necessary steps to be 
taken to prevent saliva and mucus causing caries. 



THE PREVENTION OF CERTAIN DIETETIC HABITS WHICH 
TEND TO INDUCE DENTAL CARIES 

It is well to recognize that certain habits and pref- 
erences, if indulged in, tend to give rise to caries and 
may be prevented. Thus, for example, the bolting 
of lumps of food, which, by robbing the teeth of the 
natural detergent effects of such foods, ought to be 
prevented. This habit usually comes about in young 
children through habituating them to a more or less 
exclusively soft diet, in older children it has a like cause, 
often aggravated by tender or even decayed teeth. 



DIETETIC HABITS 23 

It is obvious that the teeth in these cases must be put 
right or got rid of by the dentist, and a diet consisting 
of food which stimulates mastication (e.g., crisp toast, 
dry rusks, etc., and in older children apples, meat, nuts, 
etc.), allowed to form part of the meal. Other habits 
such as eating sweets or farinaceous foods, together 
with milk on going to bed, must be simply stopped. 
With regard to the habit of eating sweets and highly 
sweetened foods, and the attempt to break the habit 
or the craving for such foods, more difficulty may be 
experienced, more especially if such habits and cravings 
have already been established. From an analysis of 
cases in which a large amount of food requiring mastica- 
tion formed part of the daily regime it would appear 
that the desire for sweets originates to a certain extent 
from the habit of giving young children an almost 
exclusively soft diet, for in the majority of cases to be 
referred to, when the children were brought up on food 
requiring mastication, they seemed to prefer spending 
their spare cash on toys and not on sweets. In two 
cases under my own care the elder one (11 years) has 
never spent one penny on sweets, and the younger 
(6 years) only one penny (probably more for the pleasure 
of imitating his nurse than for the desire of eating 
sweets), but this has not occurred a second time, no 
doubt because the desire for toys exceeds his desire for 
sweets. In these two cases there was no injunction 
against buying or eating sweets (so long as they were 
not eaten between meals). The parents were what 
may be called notorious sweet-eaters in childhood. 
Other cases, although not so marked, seem to confirm 
the supposition that the craving for sweets varies in 
the manner indicated with the nature of the diet. 
Possibly such craving results from cheating the palate 
by the soft diet passing the palate quickly, while the 
amount of carbohydrate consumed can hardly be 
instinctively appreciated. No doubt, also, when 
children habitually end their meal with fresh ripe fruits 
they are more difficult to please with sweets, for fruits 



24 DIETETIC HABITS 

are sweet enough themselves and the aromatic flavours 
of fruit are but imperfectly imitated by the extra- 
ordinary chemicals which are incorporated with sweets 
to give them the flavours present in fruits. Moreover, 
if the adoption of such a type of diet will not stop the 
craving for sweets, there is no reason why the habit 
should not be stopped as far as possible by command. 
There are reasons for believing that in a natural state 
the supply of sugar was so limited that under such 
conditions an almost unlimited desire for it could not 
have been harmful. Nature supplied the restriction. 
In modern times it may be that parents must make the 
restriction if otherwise correct feeding does not prevent 
the desire. 



Chapter II 

THE PREVENTION OF THE lADIEDIATE OR 
EXCITING CAUSE OF CARIES 

In our survey of the predisposing causes, a general 
statement of the cause of caries was made which is now 
generally admitted ; but it should perhaps be men- 
tioned that a somewhat different conception of the 
cause of the disease was, and still may be, held. It 
is important to have an even more definite conception of 
the nature of the immediate or exciting cause when 
entering upon a consideration of the means to be taken 
for its prevention. Until recently it appears to have 
been assumed that the bacteria were to be regarded 
as the exciting cause and that meals containing 
fermentable carbohydrates suppHed the pabulum 
necessary for the bacteria. That, in fact, except in the 
case of an exclusively meat diet, the carbohydrates in 
the meals always supplied the necessary and invariable 
conditions requisite for the micro-organisms to cause 
caries, provided only that the resistive forces in the 
tooth or in the saliva did not nullify or counteract the 
effects of the acid produced by the micro-organisms. 
Why, under such circumstances some teeth decayed in 
some mouths and did not decay in others was explained 
by assuming the existence of some unrecognised sus- 
ceptibility or immunity. It w^as assumed as a natural 
corollary to this hypothesis that the rational way of 
preventing caries was to make the mouth as nearly 
as possible an aseptic chamber by the use of antiseptic 
mouthwashes. Nevertheless, in England at least, 
it was held that what had been established 

C *5 



26 1 EXCITING CAUSE 

was the pathology of the disease, and that the 
etiology or the cause of the disease remained 
an unsolved problem. The following three quota- 
tions will indicate the attitude which came to be 
taken up. 

(i) " If we wish to deal with dental disease, we must 
first of all possess a correct knowledge of its cause. 
Do we possess that knowledge ? It is now more than 
fifteen years since Dr. W. Miller's excellent work on 
the ' Micro-organisms of the mouth ' appeared, in which 
he clearly demonstrated that caries of the teeth was 
due to the abstraction of the lime salts by acid, followed 
by the peptonizing action of bacteria, the acids being 
formed from the fermentation of carbohydrate food. 
There seemed to be a general belief, at any rate amongst 
those practising dentistry, that the cause of caries had 
been found, and the fact seemed to be lost sight of that 
all that Dr. Miller had done was to demonstrate the 
phenomena of caries, and although his researches had 
shown the channels in which further investigation 
should be pursued, the actual cause of caries 
was still unknown, and is to the present day 
unknown. "20 

(2) "In spite of Tome's classic definition of dental 
caries, and in spite of the researches of Underwood, 
Miller, Black, Leon Williams and others, we can no 
more tell why one mouth is immune and another 
riddled with caries than we could before these inves- 
tigations were made."i3 

(3) " It is frequently stated that the true cause of 
dental caries has yet to be discovered, and although 
we know the pathology of the disease through the 
investigations of Dr. Miller, the etiology is a very 
different matter. The truth of this is obvious, and yet 
. . . nearly all the searchers after the etiology have 
pursued further pathological studies in their endeavours 
to discover it."28 

It is now generally recognized, however, that the 
fact of the prevalence of caries in some mouths and not 



EXCITING CAUSE 27 

in others (and all partaking of a mixed diet), is by no 
means necessarily a proof that there is any more 
susceptibiHty or immunity to the disease in the one 
case than in the other, for the idea has gained ground 
that some foods commonly consumed actually clean 
the teeth, while other foods more commonly con- 
sumed by children leave them sticking with ferment- 
able carbohydrates, and that even the alteration in 
the sequence of foods — in one case finishing the meal 
with the detergent foodstuffs — may effect a profound 
difference in the lodging of carbohydrates consumed 
at meal times, and therefore in the prevalence of caries. 
This conception has been developed so far, that some 
now beheve susceptibility and immunity in regard 
to dental caries is, if not a misconception altogether, 
at least an almost negHgible factor which, at the present 
day, throws no Hght whatever on the means at our 
disposal to prevent the disease. Doubtless this is so, 
and no methods of preventing the unknown suscepti- 
bility to caries having been discovered or suggested, 
we must direct further attention to the means at our 
disposal for preventing caries by recognizing that the 
cause of caries is the prolonged retention or stagnation 
of fermentable carbohydrates in more or less immediate 
contact with the teeth and undisturbed by the free access 
of saliva. It being unnecessary now to consider how 
this is influenced by the predisposing causes (these 
having been already referred to), it only remains to 
consider how the foodstuffs themselves are instrumental 
in preventing the onset of dental caries. For this 
purpose we may divide foodstuffs into two classes, 
namely, those which tend to leave viscous and fer- 
mentable carbohydrates about the teeth and those 
which tend to brush them away. When we observe 
what actually happens during mastication we see that 
it is chiefly food of a fibrous nature which stimulates 
efficient mastication. The more or less liquid part 
and suspended particles contained in the fibrous meshes 
are expressed and swallowed, while the fibrous part 



28 EXCITING CADISE 

is, again and again subjected to crushing and disinte- 
gration between the teeth. If an apple, for example, is 
thoroughly masticated, the sweet juices are expressed 
and during the early part of the process these sweet 
juices are tasted. At the end of the process, however, 
the disintegrated fibrous mass is practically tasteless. 
The sweet carbohydrates and suspended particles are 
swallowed first, while during the process the more 
fibrillar part has been stimulating mastication, in- 
salivation and dislodgment of food particles and 
bacteria. Similarly meat and potatoes or any of the 
common combinations of foods which are so naturally 
chosen and consumed by adults exhibit a similar 
phenomenon, but when we turn to the foods which 
children are at present compelled to live upon very 
largely, e.g., milk, porridge and milk, sloppy milk 
puddings, bread soaked in milk, potatoes and gravy, 
bread and jam, etc., we realize the absolute impossi- 
bility of efficient mastication being carried on. We 
realize further that what really is stimulated is simply 
a mechanical movement of the jaws which helps to 
plaster the sticky carbohydrates into the crevices of the 
teeth in which the bacteria — fed from previous meals 
and incubated in the intervals — are lying in readiness 
for the production of further quantities of acid destined 
to decalcify the enamel of the teeth. Hitherto, as 
has been noted, it was customary to regard bacteria 
as the exciting cause of the caries, but when we consider 
the fact that it is only when carbohydrates are made 
to lodge unduly with the ever-present biactera that 
acid is produced, we might perhaps with greater 
propriety say that it is the carbohydrate which is the 
exciting cause. Indeed, this is now very frequently 
done, for it is only when carbohydrate lodges unduly 
that the micro-organisms are excited to acid fermenta- 
tion. Moreover, if no carbohydrate lodged in the 
mouth the bacteria which are best adapted for that 
medium would be present only in innocuous numbers — 
probably many species would be prevented from 



EXCITING CAUSE 29 

proliferating in the mouth altogether — while the 
bacteria which find in the albuminous desquamated 
epithelium and other proteid substances their 
natural foods might actually be antagonistic to the 
presence of acid-forming and possibly also to 
pathogenic bacteria. StiU keeping to the view that 
the bacteria are to be regarded as the exciting 
cause of caries we recognize that the foods control 
the bacteria. 

(i) Fibrous foods which stimulate efficient masti- 
cation clean the bacteria out of the mouth altogether 
to a great extent. This is obvious, but to make assur- 
ance doubly sure I made some experiments*^ which 
resulted in showing that a given quantity of toast 
chewed before breakfast, then set aside in an incubator, 
developed acid much more rapidly and in much greater 
amount than an equal quantity of toast similarly 
chewed after breakfast. A similar result, including 
not only the relative but also the absolute quantity 
of acid produced, followed the same experiments with 
stone-milled flour (bread toasted). Most foods being 
practically sterile do not introduce bacteria into the 
mouth. 

(2) Fibrous foods which, by stimulating mastication, 
remove sticky carbohydrates, remove also the nutri- 
ment Avhich is most necessary for the development 
of bacteria most active in a carbohydrate medium, 
i.e., (a) acid-forming bacteria, and (b) bacteria which 
give rise to viscous fermentation. This latter class of 
bacteria is often overlooked, but inasmuch as it is only 
when the acid formed by bacteria is protected from 
neutralization or dilution with the sahva that decalci- 
fication of the enamel results, it is obvious that viscous 
fermentation must be reckoned with and should not be 
allowed, much less encouraged in the mouth. Thus, 
therefore, cane sugar when not sufficiently diluted or 
eaten with something of a detergent nature may possibly 
under certain circumstances be more destructive to 
the teeth than the more directly fermentable sugars. 



30 EXCITING CAUSE 

The formula which is givens* to represent the con- 
version of cane sugar into mannite and gum is as 
follows : — 

25 (C12 H22 On) + 25 (H2 0) 

=:I2(Ci2H2oOio)+24(C6Hi4 06)4-I2(C02)+I2(H20) 

(Gum). (Mannite). 

With regard to the fermentation of the grape sugar 
groups and the cane sugar groups Miller comes experi- 
mentally to the conclusion that " the one is apparently 
about as detrimental to the teeth as the other. "23b 
Probably this results from the fact that in a mixed 
bacterial culture such as we have in caries, some 
bacteria are inverting the cane sugar while others 
at the same time are producing acid from the inverted 
sugar. It would be a mistake to argue that because 
some species of bacteria cannot convert cane sugar that 
it is less harmful to the teeth than the grape sugar 
because it is not pure cultures which have to deal 
with the sugar in the mouth. 

As has been indicated in the preceding pages, food- 
stuffs reduce the number, and probably also the number 
of species, of the micro-organisms of the mouth, and 
as it has been maintained that one of the most 
important methods of preventing caries is as far as 
possible to sterilize the mouth, it may be as well to note 
that the sterilizing of the mouth cannot be regarded as a 
natural means of preventing the disease. While, 
therefore, by no means claiming that the mouth could 
be sterilized, we may at least say that the foodstuffs 
can control the micro-organisms so effectually that the 
teeth of civilized man may be as clean and free from 
caries as are the teeth of the lower animals, or certain 
savage races which do not use any artificial methods 
of cleaning the mouth. Further, we recognize the use- 
ful part which, when controlled, these micro-organisms 
may play. It is significant that there are no anti- 
septics naturally present in the mouth, and moreover, 
that the bacteria of the mouth are as constantly 



NORMAL SELF-CLEANSING 31 

present in the mouths of susceptibles as immunes, 
Dr. Miller has shown that the number of bacteria 
is almost as great in the saliva of " immunes " as in the 
saliva of " susceptibles," and that acid production by 
the bacteria, though sHghtly greater in susceptibles 
than in immunes, is so only as a rule. 21 Similarly 
leptothrix innoyninata, which " invariably occurs in 
every mouth, though by no means always in the same 
numbers "-s-- lends no support to the view that the 
constantly present bacteria necessarily induce caries. 
Dr. G. V. Black comes to a similar conclusion : he 
says " As I have cultivated micro-organisms a great 
deal, and especially m relation to this matter, I wish 
to say distinctly that the same micro-organisms are 
found growing in the mouths of persons who are 
immune to decay, as are found in the mouths of persons 
who are susceptible to decay, and those whose teeth are 
decaying rapidly, and the same micro-organisms will 
grow in the saliva of either one when used as a cultiva- 
ting medium. "-i We see from this that to call the 
micro-organisms of the mouth the cause of caries would 
throw httle or no light on the means of preventing the 
disease, and we are driven to accept the definition of 
the cause of caries already given. 



NORMAL SELF-CLEANSING PROCESSES 

The normal or natural self-cleansing processes are 
generally recognized to exist, but they are seldom 
studied or described, and yet it is by recognizing the 
nature of those self-cleansing processes that we are 
enabled to indicate scientifically what natural or arti- 
ficial means may best be relied upon for the prevention 
of caries. The consideration of these processes wdth 
regard to artificial methods of cleansing will be referred 
to hereafter ; in the meantime it will be well to recall 
certain points in natural oral h^/giene (more especially 
with reference to the nature of the foods consumed) 



32 NORMAL SELF-CLEANSING 

for, however simple it may be to arrange dietaries 
in such a way as to secure physiological cleanliness of 
the mouth, it is highly desirable to recognize the main 
features of the normal and natural processes by which 
physiological cleanliness is maintained, however com- 
plex these processes may be. For convenience in des- 
cription we may consider the processes under different 
headings, although they are more or less intimately 
associated and dependent upon each other. 

Firstly, we have the mechanical process. This 
depends, to a great extent, on the physical consistency 
of the food. When the food is of a firm and somewhat 
fibrillar consistency, it stimulates the pleasurable 
activity of efficient mastication. The teeth and gums 
are rubbed and scoured, particles of food are dislodged 
from the teeth, expressed from the bolus of food, 
entangled in the mucus saliva and sucked or pressed 
back towards the pharynx, and swallowed. In other 
words, food of such a consistency has a detergent effect. 
Highly refined or " short " and soft food has, on the 
contrary, a different effect when taken into the mouth ; 
it is simply crushed or squashed into the crevices of the 
teeth, and if it is at all of a sticky nature it remains 
impacted there. Bread and jam and cake may be 
taken as examples of such foods which tend to lodge 
about the teeth. 

Secondly, we have the chemico-physiological process. 
Food, when taken into the mouth, stimulates a flow 
of saliva, and carbohydrate food, especially if slightly 
acid^sb and firm in consistency, stimulates the secretion 
of saliva rich in ptyalin. The mastication helps to 
incorporate the ptyalin in the food, and the solid starch 
becomes partly converted into soluble sugar, which is 
ultimately expressed from the more fibrous part of 
the food and swallowed in a liquid or nearly liquid 
form. The more fibrous part is subjected to further 
mastication and lubrication with mucus before swallow- 
ing. This is, of course, the natural method of treating 
carbohydrate food, and, in passing, it may be said the 



NORMAL SELF-CLEANSING 33 

physiological method of leaving the mouth free from 
carbohydrates at the end of a meal. It should be 
remembered, however, that much sugar hampers the 
action of the ptyalin. 

Thirdly, we have the hydrodynamical process. 
With each act of mastication the saliva is mixed with 
the food, forced in certain directions between and 
about the teeth, between the food shreds, and ulti- 
mately it, together with dissolved and suspended 
particles, is swallowed. We may note here, again, that 
if the food is soft, and pappy, this hydrodynamical 
process is practically lost, as such foods do not stimulate 
efficient mastication. 

Lastly, we have a saprophytic or bacterial process. 
In the whole history of man or animal, the mouth has 
never been free from micro-organisms, and the bacterial 
flora of the mouth seems to play a part in its hygiene. 
There is no pepsin or other ferment in the mouth which 
can digest or liquefy the various albuminous shreds and 
particles which are apt to lodge between the teeth. 
But there are many of the mouth bacteria which have 
this power. In fact, these bacteria digest and liquefy 
the albuminous shreds which lodge about the teeth, 
and so allow of their dissolution. They give rise to a 
continual disintegration and removal of food particles, 
and tend to keep the teeth clean at those very situa- 
tions which are not kept clean by the natural friction 
of the food, tongue and lips. It cannot be said that 
all the bacteria which may be in the mouth are bene- 
ficial under all conditions, for even some of those 
which have the power of liquefying albuminous matter 
have also the power of producing acid when the lodging 
food particles are of a starchy, viscous or sugary 
nature. The strictly Hquefying mouth bacteria, how- 
ever, seem to be quite innocuous to the teeth, and if 
the dietary is arranged physiologically, these beneficial 
mouth bacteria are favoured, while on the other hand, 
the harmful — the more pronouncedly acid-forming 
bacteria — are, in my opinion, at least, prevented from 



34 NORMAL SELF-CLEANSING 

proliferating. This might be considered an obvious 
deduction from the fact that the kind of bacteria which 
proHferates best is that which is appropriate to the 
given medium. But it is not merely a deduction, for 
Mr. K. Goadby has observed that the number of 
putrefactive rather than the acid-forming bacteria 
preponderate in the mouths of Zulus and Kaffirs with 
good dentitions and also in monkeys, and this seems 
to result from methods of living which favour the 
cleaning away of fermentable carbohydrates. 

In perfect mouths no doubt bacteria for cleansing 
purposes are but little if at all required, for the mucous 
membrane comes up nicely over the necks of the teeth, 
finishing off almost like a fine film closely applied to 
the neck of the tooth, so that the gum margin and 
tooth present hardly a visible crevice where food 
debris could lodge. When also, together with such 
arrangement of the gum margins, the teeth are per- 
fectly regular and well-formed, extremely few food 
shreds or particles are likely to lodge after any physio- 
logically correct meal. Such perfect conditions should 
exist in the great majority of children at least, for in 
those children to be referred to later, who were dieted 
physiologically, the conditions referred to remained 
practically perfect. 

While recognizing the beneficent role of physio- 
logically correct meals, it may also be noted that 
together with the foods taken at meals there are also 
generally a number of adventitious bacteria taken 
into the mouth, especially after eating certain kinds 
of food, e.g., cheese. They may remain there for some 
little time, but they do not appear to hold their own 
in the mouth, what are called the mouth bacteria 
being more adapted for the environment. Those 
adventitious bacteria are gradually swallowed till in a 
short time none are to be found in the mouth. Dr. 
Miller has shown experimentally that even bacteria, 
which can hold their own for a time when added to 
saliva, are, when taken into the mouth, rapidly got rid 



nor:\lil self-cleansing 35 

of from the mouth. Thus after rinsing the mouth 
thoroughly with a bouillon culture of Bacillus prodi- 
giosus containing over 2,000,000,000 bacilli, so as to 
give them a good chance of estabhshing themselves, 
he found an astonishingly rapid decrease of bacteria, 
so that at the end of four hours the prodigiosus had 
disappeared from the mouth. Thus while adventitious 
bacteria find their way into the mouth they are rapidly 
got rid of, while the mouth bacteria remain and pro- 
liferate wdth such tenacity that, as Dr. Black's extended 
research shows, about twelve species are practically 
constantly to be found in the mouth if diligently 
searched for. This number is augmented in some 
mouths, for if abnormal conditions exist in any mouth, 
bacteria appropriate to the abnormal environment 
are not long in finding the suitable nidus for their 
existence and development. The mouth is so exposed 
to bacterial infection that whenever it presents a suit- 
able soil for the development of any common species 
of bacteria, then such bacteria will gain a foothold, 
and without such suitable soil it seems impossible 
for any species of bacteria to have more than a transient 
existence in the mouth. 

It may be mentioned here that a bacteriological 
method for the prevention of caries has been sug- 
gested.14 It consists in endeavouring to sow some 
adventitious bacteria in the mouth which will be antag- 
onistic to or crowd out the (acid-forming) bacteria 
already present. As this method is accompanied by 
regulations regarding artificial cleansing and the use 
of lotions antagonistic to the development of acid- 
forming bacteria, and is then followed by regulations 
as to diet, and as the results have not and cannot 
be claimed to be better than the results which have 
been obtained even from regulations in diet alone, 
it would be difficult to say that the bacteriological 
procedures have anything to do with the good results 
which have been claimed by its author. Moreover, 
the method seems only to be applicable after caries 



36 NORMAL SELF-CLEANSING 

has actually manifested itself, and so can hardly be 
considered satisfactory. The suggested method has 
much interest, however, in showing the different 
attitude of bacteriologists towards the bacteria in the 
mouth, from that which existed in the days when 
antiseptics and artificial brushing were the sole methods 
relied upon for preventing caries, and when attention 
to diet and dietetics as a means of preventing decay 
found no place in our text-books on dental surgery. 



Chapter III 

DIET IN INFANCY AND CHILDHOOD IN 
RELATION TO THE PREVENTION OF 
DENTAL CARIES 

The diet in infancy and childhood may be considered 
at three stages. Firstly, the diet of the toothless infant. 
This should be mother's milk, and as there is unanimity 
upon this point, all that is necessary to advocate further 
is that investigations into the causes of deficient lacta- 
tion in women should be made, for it seems certain that 
the substitution of other kinds of milk and all means to 
find a perfect substitute must always remain unsatis- 
factory. The second stage to which it is necessary 
to direct attention is one of transition, transition on 
the one hand from the toothless infant to the child 
with a complete set of temporary teeth, ond on the other 
from the milk diet to the soHd and varied diet for which 
the child's teeth and alimentary canal are so admirably 
adapted. This period of transition is most important. 
It will be remembered that while " the child starts 
life edentulous and gradually acquires teeth, other 
parts of the aHmentary tract in the healthy subject 
undergo concordant changes. "^^ Now for the first six 
or nine months of a child's fife it has been accustomed 
to extracting Hquid from the mother's breast, and 
through all the ages of man's evolution nothing was 
mixed with this milk. When, with increasing age and 
concomitant changes, the first article of food was pre- 
sented to the child it was given at a different time from 



38 DIET IN CHILDHOOD 

the sucking of the milk. It must be obvious that in 
a state of Nature it was utterly impossible to soak food 
in milk in order to effect the transition from mother's 
milk to the ordinary foods of children and adults. 
Moreover, there is no precedent which could in any way 
be interpreted as justifying the method of transition 
from milk to solid food which has been so universally 
adopted by the medical profession. How the transi- 
tion from milk to solid food is recommended may be 
exemplified by a few extracts from a recent authori- 
tative textbook published " to aid the young 
practitioner " of medicine. After nine months, the 
author says, " Dilution of the milk is not necessary. 
. . . Some solid food may be added in the shape 
of boiled bread, or porridge, or pudding. These 
additions must be small in quantity at first." Then 
when the child is twelve months old, he says, " The 
porridge may be made thicker and of coarser oatmeal. 
A little potato and gravy or half an egg may be given 
once a day. Soft bread and butter or dripping may be 
taken. "^^^ A transition from milk to solid food such 
as is exemplified in the above, never existed in the 
evolution of man or animal. For simplicity, attention 
may be limited to bread soaked in milk, for it illus- 
trates the pap feeding principle as well as anything 
else, and it is the most generally recommended food 
for infants who are beginning to be allowed something 
solid in addition to milk. Now what happens when an 
infant hitherto accustomed to milk is given bread well 
soaked in milk ? The first noticeable effect is that the 
infant gulps down the milk-soaked bread and milk 
without any attempt at retaining it in the mouth or 
mixing it with saliva. The starchy matter in the bread, 
is, therefore, washed into the stomach without any 
insalivation without any conversion of the starch, 
and without any preparation for digestion in the 
stomach. The physiological effect which the retention 
and mastication or gnawing of food in the mouth 
produces is practically lost, and the flow of digestive 



DIET IN CHILDHOOD 39 

juices in the stomach is correspondingly lessened. The 
palate is cheated, for large amounts of carbohydrates 
are washed rapidly past it, and instead of appreciating 
the amount of converted starch, or rather of uncon- 
verted starch, which the child has consumed, it craves 
for more of that very substance of which it has already 
consumed too much, in other words, it develops an 
abnormal craving for sugar. Further, by becoming 
habituated to swallowing sohd food it soon loses that 
automatic mechanism which arrests soHd food in the 
mouth till it has become liquefied and prepared for 
deglutition. 

At a later stage, say, about the thirteenth month, 
when the first temporary molars have taken their 
positions, what happens when the child is restricted 
to this soft diet ? The previous troubles continue and 
the teeth get dirty and tender from want of use ; 
later they become carious and the tenderness 
increases, while for the sme reason mastication is 
not performed and so these troubles and others 
resulting therefrom become more or less thoroughly 
estabhshed. 

But it may be asked, Why, then, has the milk-soaked 
diet been brought into existence ? Well, no doubt 
it is because milk was considered the most excellent 
food for children. But it was found that cow's milk, 
when it was given to children undiluted, formed large 
clots in the stomach and thence consequently led 
to various intestinal troubles. This did not dissuade 
those in authoritative positions from still advocating 
undiluted milk. No, they said, soak bread in the 
milk so that the clots will be broken up. And 
if there is choking and spluttering see that it is 
thoroughly soft and well broken up before the child 
gets it. 

Now why should a hint not be taken from Nature ? 
Mother's milk when the child reaches nine months or 
a year does not become more sohd, rather the reverse. 
Suppose we give cow's milk, why should we make it 



40 DIET IN CHILDHOOD 

less diluted than it was before, seeing that the time is 
beginning to approach when the child will and can eat 
solid food and drink liquid water ? The child has been 
accustomed for all the months it has existed to have 
its mother's nipple in its mouth (or an artificial sub- 
stitute), and from this it has been able to express or 
suck liquid food. When it is determined to give the 
child solid food, why not let it get a solid piece into its 
mouth ? In other words, why not let it have a slice 
of bread, or better perhaps, toasted bread and butter ? 
No doubt the child feels that toast and butter is not 
its mother's breast, and it certainly subjects the toast 
to the influence of its teeth. It gnaws it and sucks 
it ; the gnawing induces a flow of saliva and the 
ptyalin converts the starch. The child continues to 
suck much as it sucked its mother's breast, and its 
palate appreciates that it is actually sucking liquid 
out of the solid toast. Gradually the toast disappears, 
practically in the form of liquid down the child's 
throat, thoroughly prepared for further digestion in 
the stomach. Before the fourteenth month, or at 
least before the first temporary molars erupt, true 
mastication, of course, is not performed. It is gnawing 
which is indulged in, and it certainly and instinctively 
is indulged in by all children. After the child has had 
its toast to supplement its milk diet, say, twice a day 
for a month or two, then other things may be added, 
such as rusks and milk puddings made sufficiently 
solid, and as there is not an excess of albumen in the 
milk (it having been diluted), boiled fish and chicken 
may be given in small amounts. 

I have had some little experience with this method 
of feeding infants, and can say most unhesitatingly 
that coughing, choking or spluttering has been con- 
spicuous only for its total absence. And those who 
have adopted similar methods with children from 
the beginning have been impressed or even astonished 
by this fact. But this is not all, the desire for hard 
food remains. The teeth do not become tender nor 



DIET IN CHILDHOOD 41 

the mouth dirty nor the teeth carious. The palate is 
not cheated, and the desire for excess of food or sweets 
does not exist. The aHmentary canal performs its 
functions in a natural and healthy manner, and 
by the age of 2|, when it has its full set of 
temporary teeth, the child can and may be allowed 
to triturate practically any food which adults 
habitually eat. 

With regard to the third stage, that is, the diet of 
children after they have their twenty temporary teeth, 
but Httle need be said here. The principles on which it 
is based, however, are the result of careful enquiry, 
experience and a study of the evolution of man and his 
diet, together with a recognition of the needs of civihzed 
hfe. 

It should consist of three meals daily, and nothing 
between meals except water when desired. 

It should contain a sufficiency of soHd food of a 
consistency which will ensure thorough cleansing of 
the teeth by the food and stimulate the pleasurable 
activity of efficient mastication so as to prevent the 
child acquiring the habit of bolting its food. 
Different ways of doing this will no doubt suggest 
themselves, but perhaps the simplest way is to have 
toast, baked bread, or crusty bread rolls instead of 
plain bread or porridge. 

Lastly, the meal should be arranged physiologically. 
All that need be said at this point, however, is that the 
meal must not terminate with concentrated and easily 
fermentable carbohydrates which lodge or stick about 
the teeth. Thus, therefore, no meal should end with 
bread and marmalade or jam, nor should it end with 
sweet milk puddings or foods with a large amount of 
sugar. If these things are eaten they must be 
followed by fresh fruit, and of all the fresh fruits 
which clean the mouth and teeth the apple is the 
best. 

The nature of the diet after the child has a complete 
set of temporary teeth is of so much importance that, 



42 DIET IN CHILDHOOD 

in- order to indicate the exact nature of the methods and 
principles of dietetics involved and the various reasons 
for advocating them, it may be well to mention a few 
points in the history of the investigations which led, 
as far as I am concerned, to the advocacy and adoption 
of the methods. 



Chapter IV 

THE NATURAL HYGIENIC METHOD OF PRE- 
VENTING DENTAL CARIES AND REASONS 
FOR INSISTING ON ITS ADOPTION 

About twenty years ago circumstances had caused 
me to become keenly interested in the problem of 
heredity, and rightly or wrongly I came to be a firm 
believer in the then new doctrine that acquired char- 
acters were not inherited, and a fortiori that mutila- 
tions were not inherited. Equally was I opposed to the 
Lamarckian doctrine, that use and disuse of any organ 
had an effect on the hereditary potentialities of such 
organ. These being my behefs, it was impossible for 
me to subscribe to the dictum that dental caries was so 
markedly hereditary that no one would even suggest 
the contrary. To me the theory of the hereditary 
degeneracy of the teeth was unthinkable, and from the 
point of view of prevention it was absolutely useless. 
But just because the hereditary view was untenable 
so much the more was the true solution of the problems 
of causation important, for if the etiological factors 
were essentially environmental, then this it would be 
in our power to alter for the better. Nor did the 
various developmental theories appear to help much 
in the solution of the problem, for although certain 
facts, such as the elimination of phosphates from bread, 
seem to offer a plausible explanation of the generalized 
augmentation in the amount of caries, nevertheless 
the fact did not in any way account for the prevalence 



44 HYGIENIC METHOD 

of the disease in certain families and its absence in 
others, which equally consumed the same bread. 
Moreover the fact that less phosphates are absorbed 
from wholemeal breadi^ than from white bread abso- 
lutely negatived this view. The theory that in districts 
where the water is deficient in lime salts there was more 
caries than in districts where the lime salts in water were 
abundant, did not in any way account for the increased 
prevalence of caries in the same district, nor for the 
variable amount of caries in any one district. More- 
over, it was not my experience that the amount of 
caries did vary with the proportion of lime salt in the 
drinking water. Still one other developmental theory 
had to be considered, namely, the theory that the soft 
nature of our civilized foods gave rise to a type of tooth 
which was specially liable to decay. This seemed to 
me quite untenable, because the crowns of the tem- 
porary teeth, which are so " susceptible " to decay, 
are formed partly before birth and completely before 
the child has left off sucking liquid milk. It became 
apparent that the then prevalent theories would not 
bear analysis. We had all the facts at our disposal, 
which utterly condemned such theories as we have 
referred to. We had, indeed, too many facts which, 
for want of a correct theory, seemed only to confuse 
investigators and make the subject appear more hope- 
lessly complicated. There seemed to be only two 
ideas which appeared to contain a germ of truth. The 
first was the once popular belief that sugar was bad 
for the teeth. Now, although this idea probably 
had originally no better foundation than that children 
with carious teeth frequently brought on toothache 
by eating sweets, yet the idea was not antagonistic 
to the pathology of the disease, and what is of more 
consequence, it seemed on the whole to be supported by 
facts which were frequently brought before us in our 
routine practice. It is true that the amount of caries 
was by no means constantly related to the amount of 
sugar consumed. Moreover, occasionally cases cropped 



HYGIENIC METHOD 45 

up which appeared to contradict the hj-pothesis, and 
nothing is more destructive to a theory than demon- 
strable facts which cannot be made to harmonize 
with it. 

It was pointed out that children living in sugar-cane 
plantations and chewing sugar-cane for many hours 
a day were remarkably free from caries, and this supplied 
a generally accepted fact which more or less expunged 
the sugar hypothesis among the educated classes. 
The second idea which appeared to contain a germ of 
truth was the relation between attrition of the teeth 
and freedom from caries. This was also a general 
statement and was not always true in particular cases, 
or even in particular races ; still, in general, it was 
admittedly true. We see, however, that neither of 
these h}'potheses seemed to be of practical value, 
because in the same country and under supposed similar 
dietetic regime we found a considerable percentage of 
people with perfect teeth, and also a large number with 
their teeth most hopelessly ravaged by caries. Indeed, 
the question of the food in relation to the prevalence 
of dental caries gradually came to be regarded among 
dentists as an untenable theory, while the supposed 
susceptibility of some and immunity of others became 
an accepted fact, and the solution of this problem of 
susceptibility and immunity became the all-important 
and all-absorbing subject among the prominent and 
thoughtful members of the dental profession. Not- 
withstanding all this, however, there was a lurking 
behef that although nothing had been found in the 
modern foods which appeared to help us to solve this 
problem of why some teeth were ravaged by caries 
while others were perfectly free from the disease, yet 
I had hope that a more thorough investigation into the 
foods and dietetic habits of the " susceptible " and of 
the " immune " might throw some light upon the 
subject.'i^ It was necessary to have some hypothesis, 
of course, to direct one's investigation to profitable 
account. Indiscriminate search, however scientifically 



46 HYGIENIC METHOD 

tabulated, seemed to me to offer little hope of doing 
anything but making confusion worse confounded. 
In my preliminary investigations many hypotheses 
were made and were successively more or less com- 
pletely killed by the facts which were revealed. Still 
certain things became apparent, and one was that the 
diet and dietetic habits of children in the same country, 
even in the same districts, differed considerably ; 
another w^as that what might be considered natural 
foods as opposed to the highly refined or artifically 
prepared foods, were consumed in quite different 
quantities hy different people. These early investiga- 
tions and a knowledge of the pathology of dental caries 
led me to investigate whether the refined foods of the 
present day might be more lodgable than the less refined 
and less prepared foods of past ages. An investigation 
into the relative lodgability of the various foodstuffs 
in the crevices of the teeth was therefore undertaken. 
I made about 600 observations^* in one mouth after 
meals and found that the " short," highly refined 
carbohj^drate foods tended to lodge unduly in certain 
crevices about the teeth, while the foods of a more 
fibrillar or fibrous character did not tend to lodge 
in such situations so readily. Indeed, it gradually 
became apparent that the more fibrous foods had a 
detergent effect, that they stimulated efficient masti- 
cation and consequently might be presumed to prevent 
the undue lodgment of bacteria and mixed foods 
which were known to give rise to acid fermentation 
and to the destruction of the teeth. The crevices 
in the teeth of the mouth referred to were abnormal 
and contained fillings, so that it was necessary to 
verify all such observations in other mouths. It con- 
sequently has been my practice for the last ten years 
or so to inspect the crevices of all children's teeth 
immediately they sit down on the dental chair, and then 
ask them what they had eaten last. Moreover, with 
two children constantly under my observation, I have 
been able to vary the foods at pleasure and observe 



HYGIENIC METHOD 47 

the lodgability of any particular food or the detergent 
effect of any particular food. In these ways a very large 
number of observations have been made which taught 
me that some foods are Hkely to lodge about the 
teeth and cause caries, while other kinds of foods tended 
to clean away lodging foodstuffs and therefore to 
prevent caries. This hypothesis also received general 
confirmation from an investigation into the state of 
the teeth of savages, for it was found that the amount 
of caries varied inversely ^\dth the coarse and fibrous 
nature of the foods. The relative freedom from caries 
among those people and races whose teeth had under- 
gone attrition still further corroborated the theory, 
and furnished an explanation of the fact that the teeth 
of children who chewed sugar-cane were relatively free 
from caries, for sugar-cane is a highly fibrous foodstuff, 
and detergent in its effects, while the sticky sweets 
consumed by civiHzed children are not detergent 
and therefore induce caries. On reconsidering the 
subject it was evident that the refined foods of the 
civih/ed were even more nutritious and more easily 
digested than the foods of the savages, so that we had 
no ground whatever for the assumption that the teeth 
were deprived of nourishment or lime salts or anything 
else which would injure their development. More- 
over, it became evident that the chief chemical change 
in the foodstuffs was a decreased consumption of the 
carbohydrate known as cellulose, and the chief physical 
change was also to be found in the refinement and 
softening or elimination of the cellulose. We may now 
refer to some of the general changes which the food of 
civiHzed man has undergone since he emerged from the 
savage state. 

Cellulose in the natural or uncooked state is, as a rule, 
of a consistency which stimulates vigorous mastica- 
tion, but in civiHzed countries the ceUulose is cooked, 
softened and often altogether extracted from the food, 
so that the detergent effect which this has in its natural 
state is almost completely lost. Indeed, it may be 



48 HYGIENIC METHOD 

presumed that in the state in which it is frequently 
presented it helps to clog the crevices rather than to 
brush away the bacteria and fermentable food particles 
which may lodge about the teeth. In fact, the absence 
of cellulose in a form which should stimulate the 
pleasurable activity of efificient mastication practically 
nullifies the mechanical, the hydrodynamical and, to a 
certain extent, the chemico-physiological self-cleansing 
process of the mouth. 

The next carbohydrate to which we may briefly 
refer is starch. This, when cooked or boiled, becomes 
of a pasty nature, and it is easily converted into 
sugar, which becomes rapidly fermentable. Starch, 
therefore, when taken in the food, unaccompanied 
by food of a detergent nature, is eminently fitted 
to lodge and undergo acid fermentation in the 
mouth. 

Lastly, we may refer to sugar. Sugar has long been 
supposed to have a deleterious effect upon the teeth. 
The investigations of Miller, however, tended to show 
in his opinion that it was to be considered as less harm- 
ful to the teeth than starch, and the fact, or at least 
the supposed fact, that children who consumed large 
quantities of sugar from the sugar-cane were relatively 
free from dental caries gave rise in the minds of most 
dentists to the idea that the " sugar-bogey " had been 
slain. And although most would admit that neither 
starch nor sugar could be beneficial, there was, of course 
little use of talking about preventing children eating 
both sugary and starchy foods. Miller based hi& 
criticism largely on the fact that sugar was readily 
soluble and was, therefore, " soon carried away, or so 
diluted with saliva as to be rendered harmless." 
Clinical evidence, however, supports the idea that the 
sugars are more harmful than the starches, no doubt 
from the fact that in addition to inversion cane-sugar 
undergoes a mannitic fermentation, forming a gummy 
substance which not only clings about the teeth, but 
also tends to catch other particles of food, and to retain 



HYGIENIC METHOD 49 

them in contact with the teeth also. Secondly, sugar 
hampers the action of the saHva, and lastly, the method 
of eating sugar in the form of bonbons causes a con- 
tinuous supply of this fermentable material to be 
available for the acid-forming bacteria lodging in the 
crevices of the teeth. With regard to the relative 
excellence of the teeth among the natives in 
the sugar-cane plantations, this is, of course, 
largely due to the fact that the fibrous cellulose of 
the cane stimulates the self-cleansing factors most 
thoroughly. 

WTiether cane or grape sugars are the most harmful 
does not appear to be definitely settled ; it seems pretty 
certain, however, as a clinical fact that sugar as usually 
consumed, sweets, marmalade, jam, etc., is markedly 
harmful to the teeth. I can imagine someone saying, 
" Well, perhaps these changes in the foodstuffs referred 
to may account for the increased prevalence of dental 
caries in a general way, but do these changes account 
for the great variation in the amount of caries which 
we see in different mouths at the present day ? " 
We see many children, for example, with almost every 
tooth more or less carious before they are more than 
five years old. On the other hand, we occasionally 
see children of the same age with every tooth free from 
any trace of disease, yet all have been brought up in 
the same country and the changes in the foodstuffs 
are common to all. 

Now it was these very groups of cases which used to 
fascinate me most. It was, indeed, these extreme 
cases that first made me come to the conclusion that 
the dietetic habits of the children with the perfect 
teeth were essentially different from the dietetic habits 
of those with the bad teeth. 

We may illustrate the two different types of diet 
which are often more or less consistently followed, by 
the following dietaries : — 

Firstly, we shall refer to the kind of meal which does 
not produce caries : — 



50 HYGIENIC METHOD 

Breakfast. Fish, bacon, toast and butter, cofiee 
and tea. 

Luncheon. Meat or poultry, potatoes, salad, baked 
bread, pudding, fresh fruit, water. 

Supper, Rusks, toast, or bread rolls and butter, 
chicken or fish, an apple, tea or coffee. 

Secondly, we may outline the kind of meal which 
induces dental caries : — 

Breakfast. Porridge and milk, bread and marma- 
lade. Then perhaps a supplementary breakfast a few 
hours after of a glass of milk and a sweet biscuit. 

Luncheon. Mashed potatoes and gravy, or minced 
meat, milk and pudding. 

Supper. Bread soaked in milk, or bread and jam, 
cocoa and cake, and a supplementary supper on going 
to bed of a glass of milk and a biscuit, or just " a tiny 
piece of chocolate." 

On comparing these two different types of diet, 
we observe that one is of a kind which stimulates 
mastication and the last thing taken leaves the mouth 
clean, or at least free from carbohydrates, so that even 
when soft food is part of the meal the mouth will be 
physiologically clean at the end of the meal. The 
other type is intended to represent the kind of meal 
which is calculated to lodge about the teeth and to 
ruin them within a few years by making efficient 
mastication and the self-cleansing of the mouth 
practically impossible, and by leaving the mouth 
sticking vvith fermentable carbohydrates and a 
virulent crop of acid-forming micro-organisms which 
have had their development encouraged by the 
previous meal. 

Since discovering, about ten years ago, the general 
tjrpe of diet which gave rise to caries, it has been my 
custom to question all children carefully about their 
diet, if their teeth were free or practically free from 
caries, and in every case it was found that the food 
habitually consumed was of the detergent tyi^e, or, if 
not altogether so, at least that it was consumed in 



HYGIENIC METHOD 51 

such a way as to leave the mouth physiologically 
clean at the end of the meal ; I cannot tell exactly 
now how many children I have examined, with perfect 
teeth. The number probably does not amount to 
fifty, for perfect teeth are very rare in England. One 
thing is certain, however, I have not yet seen one single 
child where the teeth were perfectly free from caries 
which was not brought up on a t}^e of diet such as 
I have indicated does not produce dental caries. On 
the other hand, many mouths were seen devastated by 
caries, and I have certainly seen several hundred such 
mouths, but in these cases the type of diet habitually 
consumed and the dietetic habits engendered have 
invariably been such as result from the caries-producing 
type of diet which I have illustrated. 

This is a brief outline of the somewhat prolonged 
investigation which has, in my opinion, resulted in a 
solution of the problem of the prevalence of dental 
caries, and for the assertion that susceptibility and 
immunity are almost invariably assumed, through lack 
of knowledge of the cause as distinguished from the 
pathology of the disease. I have tried to indicate some 
of the evidence upon which the theory was based and 
the evidence also which corroborated the theory. It 
now only remains to bring forward even more startling 
evidence, and to make it more obvious to those who 
did not or would not take the trouble to follow the 
facts and arguments which demonstrated the truth of 
the theory. It appeared to me that the most satis- 
factory way of doing this would be to get people with 
infant children to put the theory into practice. Four- 
teen children have been subjected to this test, and at 
ages ranging from 5 to 7 years their teeth were examined 
with the result that not one tooth of any of these children 
showed the sHghtest trace of caries. This may not seem 
a large number, but when we remember that in England 
a similar number of children of the same class would 
certainly have had eighty to ninety carious teeth 
among them at the same age, we see that according 



52 HYGIENIC METHOD 

even to this alone there is overwhelming probability 
or practical proof that the theory is correct. Over 
and above this we must remember that this applica- 
tion of the principles of prevention is but a small part 
of the evidence which has enabled us to prove the truth 
of the theory. 



Chapter V 

ARTIFICIAL METHODS OF PREVENTING 
DENTAL CARIES 

There are several different procedures which in practice 
are usually combined in cleaning the teeth artificially. 
It will be convenient, however, to consider these under 
different headings, while bearing in mind that certain 
combinations are frequently to be preferred to any one 
artificial procedure. 

MOUTHWASHES 

The simplest and most inoffensive artificial procedure 
is the rinsing of the mouth after meals with water. 
It is well when explaining the value of this, to tell 
patients to observe the water which is ejected from 
the mouth after rinsing it about the teeth, for by the 
disappearance of the milkiness of the ejected water 
they will be able to see and appreciate how much has 
been washed away by this process. Several mouth- 
fuls of water may thus be used until the ejected water 
comes from the mouth practically free from milkiness. 
The efficacy of such a mouthwash depends on its 
simple mechanical or rather hydrodynamical effect 
on the more or less loose remains of foodstuffs and 
bacteria. The usefulness of the mouthwash may be 
enhanced somewhat by the addition of aromatic 
flavourings which not only may be made to leave the 
mouth with a pleasant and cleanly feeling, but also 
will stimulate the salivary secretion and thus prolong 

53 



54 ARTIFICIAL METHODS 

the action of the washing-out process with the natural 
mouthwash. A slight acidity in the mouthwash 
is also beneficial in stimulating the flow of saliva, and 
though it may be very transient and slight, the effect 
of the acid on the mouth bacteria should tend to inhibit 
the growth of the micro-organisms, more especially 
the acid-forming micro-organisms. 

ANTISEPTICS 

The mouthwashes may also be made antiseptic. 
Much good was at one time expected to be derived from 
their habitual use, but this arose no doubt to a certain 
extent from mistaking the pathology for the etiology 
of the disease. At all events, the prevention of the 
undue lodgment of carbohydrates was not the aim 
or object of antiseptics. The fact that the micro- 
organisms of the mouth secluded and incorporated 
with debris, etc., are able to resist the transient presence 
of antiseptics in such strengths as would not injure 
the mucus membrane was overlooked to a great extent, 
and it has been shown that in order to get any appre- 
ciable bactericidal action it is necessary to keep the 
antiseptic mouthwashes — which have so far been 
devised — in the mouth for a very inconveniently long 
time. Furthermore, antiseptics do not dissolve the 
bacteria or viscid food remains which more or less 
constantly cover the bacteria at those parts of the 
teeth which are not kept clean by the friction of the 
food. Even those antiseptics which give off nascent 
oxygen and are supposed to penetrate, do not appear 
to have any appreciable effect. Thus if some of the 
materia alba is observed before such antiseptic wash 
is used, and then immediately afterwards, no appre- 
ciable difference is observable even though much bub- 
bling of nascent oxygen has taken place. Lastly, no 
antiseptic has yet been brought forward which will 
help rather than retard the liquefaction and consequent 
T-emoval of albuminous substances which may have 



ARTIFICIAL METHODS 55 

collected in abnormally great and therefore harmful 
amounts. Nevertheless, anti-septic mouthwashes have 
their uses, but these are for the sake of surgical clean- 
liness before a surgical operation or for the treatment 
of some diseases of the mouth rather than for daily- 
use in the prevention of caries — and their use must be 
preceded by thorough and careful cleansing by expert 
hands if anything approaching asepsis is to be hoped 
for. But that such thorough cleansing and sterilizing 
the mouth is desirable — indeed imperative — before 
operations on the tonsils, larynx, etc., 21 and no doubt 
more especially operations on the oesophagus and 
stomach, seems to have been proved beyond the 
possibility of a doubt. Under such circumstances it is 
certainly preferable to risk a sUght superficial distur- 
bance of the mucous membrane of the mouth than 
septic infection of a wound. 

In a general way it may be said that the mucus 
membrane (or skin) is the first fine of defence against 
pathogenic micro-organisms when this is intact and 
healthy, and in ordinary daily life it is most essential 
that the mucous membrane of the mouth should be in a 
perfectly healthy state, and nothing should be used in a 
routine way which may injure its vitaHty. Unless 
it is known to be unhealthy or not intact, it is doubtful 
whether the risk of injuring the mucous membrane 
by the daily use of antiseptics can be advantageously 
recommended. In this connection the Lancet, 
after reviewing some investigations on this subject, 
concluded by saying, " It is obvious that further 
investigations must be undertaken before the daily use 
of an antiseptic mouthwash by healthy persons can be 
recommended."2s And a like conclusion was indicated 
in the British Medical Journal.^'^ 



THE TOOTHBRUSH 

The use of the toothbrush is, or has been, relied 
upon more generally than any other procedure. 



56 ARTIFICIAL METHODS 

Unfortunately it is not so satisfactory as used often to 
be supposed, for even when carefully and skilfully used 
it is difficult to get it to brush the teeth on their 
approximal surfaces. Nor is its use free from the 
likelihood of abuse. The delicate gingival margins are 
often injured, more especially over the front teeth, 
especially those which are prominent and situated on 
the left side of the mouth, when the brush is frequently 
too vigorously used by right-handed persons. When 
but gentle pressure is used so as to avoid injury to the 
gum margins the bristles of the brush do but little good 
in removing any adherent matter from the crevices of 
or between the teeth if it is at all of a sticky nature ; 
so that after the toothbrush has been used one may 
easily scrape away soft adherent matter even from 
between the front teeth, and if a phantom set of teeth 
or a stearined model is covered with a somewhat 
sticky and coloured material and then brushed as well 
as the intelligent layman may be presumed to do it, 
it will be seen that the crevices, say, of the molars, are 
but imperfectly cleaned and the interdental spaces are 
not cleaned at all. The illustrations on frontispiece 
of a stearined model treated in this way indicate how 
ineffectual the toothbrush always is in cleaning away 
adherent matter except at those parts of the tooth 
which are not liable to have food adherent to them, 
and where consequently the teeth are not liable to 
decay. 

Some of the mouth bacteria are very adliesive and 
require distinctly vigorous brushing to dislodge them 
from crevices or partly secluded spots and the tooth- 
brush can hardly compare with detergent foods for 
their removal. When we remember that during 
mastication the jaws exert a pressure of from 60 to 90 
pounds3 on meat and fibrous foods of a detergent kind 
generally, we realize the certainty with which the 
crevices of the teeth on the masticating surface will be 
cleaned of adherent micro-organisms. Especially is 
this so when we take into consideration the fact that 



ARTIFICIAL METHODS 



57 



the pressure and grinding motion is repeated hundreds, 
perhaps sometimes thousands, of times during the tak- 
ing of a substantial meal. Of course, if soft foods are 
eaten the micro-organisms cannot be removed from 
the crevices, and the carbohydrates which are taken 
during the meal may, to a certain extent, be gently 
pressed into the crevices and thus simply stimulate 
the growth of the bacteria and the acid that they 
produce. It is when matted masses or plaques of 
bacteria are thus furnished with carbohydrate food and 
protected from the beneficient effects of the sahva, 
that caries is certainly produced. Even though at the 
end of the meal the superficial part of such carbohy- 
drates were brushed away to a considerable extent, 
sufficient might be left to supply the bacterial 
plaque with pabulum enough to produce caries 
more or less rapidly. This is important and may 
be represented somewhat diagrammatically by the 
accompanying drawing of a section through a molar 
tooth. 

In the one case 
(Fig. A) the crevices 
are supposed to have 
been freed from 
micro-organisms by 
efficient mastication 
of detergent food 

^r^^eoM.fpt^Rre - during the meal, but 

' a httle carbohydrate 

is represented as 
having been left. 
When this begins to 
rj. I ferment it will begin 
^ / superficially, as the 
bacteria of the mouth will necessarily come in 
contact with the outer part of the carbohydrate first. 
Further, the number of micro-organisms derived from 
the saliva after a meal is relatively small, and as they 
eat down into the carbohydrate, so at the same time 



e^cTtRjp* 





58 ARTIFICIAL METHODS 

is the carbohydrate washed away more or less by the 
saHva. 

In the other case (Fig. B) the bacterial plaque 
not having been brushed away hy food requiring 
efficient mastication, the carbohydrate which remains 
in the mouth lies as a covering over the plaque and the 
micro-organisms immediately give rise to acid fer- 
mentation and decalcification of the tooth. The micro- 
organisms are actually present in situ in masses and 
protected from the neutralizing of the acid formed by 
the overlying carbohydrate. 

It is hardly sufficiently realized how difficult it is 
to clean crevices with a toothbrush except, perhaps, 
by those who have tried to clean an ordinary hair 
comb, or to polish crevices in metals with a brush. 
In this latter case when the crevices are anything like 
as deep as they usually are in molar teeth it appears to 
be quite a hopeless procedure. Nevertheless the teeth 
can be cleaned to a certain extent with a toothbrush — 
provided that unhygienic meals have left them dirty — 
and if it is attempted to clean only the masticating 
surfaces of the molars and premolars, good without 
harm will assuredly result ; but if any serious attempt 
is made to clean the interdental spaces with a tooth- 
brush of any kind yet devised, a serious risk is run of 
injuring the gingival margins with the bristles of the 
brush. 

From the point of view of the dental toilet rather 
than from that of the prevention of caries the tooth- 
brush has its uses. It should, however, be gently and 
carefully used, and if such gentle use does not keep 
the teeth clean to all appearances, then it is imperative 
to have the teeth cleaned periodically by skilled hands 
furnished with all the necessary instruments and 
accessories required. 

Before recession of the gums has taken place the 
crevices between the teeth and the interdental spaces 
are normally easily kept physiologically clean when 
appropriate food is masticated, and there should be no 



ARTIFICIAL METHODS 59 

real necessity for artificial cleaning. Later in Life, 
however, if the gums have receded, and more especially 
if in addition to this irregularities and abnormal spaces 
exist, it is necessary to aid the normal self-cleansing 
processes artificially. For this purpose, in addition to 
the toothbrush, mouthwashes may be freely used and, 
if necessary, the toothpick also. A quill toothpick is 
the most satisfactory and care should be exercised so 
that the gums may not be injured. 



TOOTHPOWDERS 

Toothpowders may be used, not for the prevention 
of caries, but to remove discoloration from the teeth. 
Unfortunately their use is frequently the cause of 
erosion more especially over the neck of some of the 
more prominent teeth. The serious results, more 
especially of the gritty toothpowders, have been fully 
exposed by the late Dr. Miller ; and it would seem that 
great care should be used in the selecting of a tooth- 
powder for daily use. Nothing of a more gritty nature 
than precipitated chalk should be used. Generally, 
however, toothpowder seems to be quite unnecessary 
even to keep the teeth looking quite white and clean, 
except among smokers. 

In some mouths, too, a dark stain — which can be 
removed with a steel instrument — is formed either in 
spite of the use of a toothpowder or possibly sometimes 
on account of it. If careful observation is made it 
will be seen that the toothbrush with toothpowder 
brushes the most prominent part of the tooth so 
thoroughly that the enamel is kept polished and even 
worn away ; the next part of the tooth not so exposed 
to the brush and toothpowder appears to have the 
mucous coating brushed away so that this dark tartar 
has nothing to prevent its deposition, and being very 
adherent to the tooth it is not brushed away. The 
third zone, ^.e., between the teeth and close to the gum 



6o ARTIFICIAL METHODS 

margin, where the mucous is only brushed partly away 
the enamel remains clean under this. The dark stain 
frequently leads to the further use and abuse of 
toothpowders. However, as has been observed, tooth- 
powders do not prevent caries ; and as their use is 
rather a matter of appearance than for the prevention 
of caries they need not be referred to further here. 

In conclusion, it may be said with reference to the 
artificial precedures in general that they are not all 
innocent and innocuous. Rinsing the mouth after 
meals, however, does good if adherent carbohydrates 
have been left in the mouth, and this procedure cannot 
be harmful, although equally satisfactory results may 
be derived from drinking water or certain other more 
refreshing fluids (preferably slightly acid and not too 
sweet) after a meal,39 while brushing the teeth with a 
medium or even hard brush used gently is generally 
useful from the point of view of appearance at least. 
Brushing the teeth after every meal and on going to 
bed can scarcely be recommended as a routine pro- 
cedure ; it diverts people's attention so thoroughly 
from the knowledge that their teeth ought to be 
cleaned by the normal physiological processes, and 
from the fact that when the meals are properly 
arranged, they do actually clear the bacteria out of 
their mouths and leave no carbohydrates behind 
which would injure the teeth or give rise to the undue 
proliferation of micro-organisms. Of course, if or 
when unhygienic meals are or must be taken, especially 
at night, then the resulting unhygienic conditions 
should be mitigated by carefully cleaning the mouth 
with toothbrush and mouthwash. It is, as a rule, 
quite inconvenient for most people to brush their 
teeth regularly except in the morning before breakfast. 
And to encourage people to bestow a little more care 
over their teeth when they do brush them once a day 
is much more useful than a perfunctory, hurried and 
perhaps too vigorous brush round. It takes at least 
twenty-four hours for the mucus or what it becomes 



ARTIFICIAL METHODS 6i 

to accumulate round the teeth — when reasonable 
habits of mastication are indulged in — to anything 
approaching the amount which could conceivably 
be anything but beneficial to the gums and teeth, and 
though the stomach, no doubt, can deal mth them it 
is rather desirable that the bacteria should be brushed 
out of the mouth (to a certain extent at least) before 
the breakfast. If they are not they will be taken into 
the stomach to a great extent during the meal to be 
disposed of there. When not immoderate in number 
or exceptional in kind the digested bacteria may 
possibly be turned to use in producing immunity to 
ubiquitous pathogenic micro-organisms \^^ but such 
immunity does not extend to caries, because caries 
is a fermentative process external to and uninfluenced 
by any vital reaction of the tissue it invades, at least 
in the early stage, and because, moreover, there is no 
such thing as true immunity to the disease. For- 
tunately there is not now much fear that artificial 
methods will take precedence over the more natural 
methods, for it has been pointed out that " there has 
been a remarkable consensus of opinion as to the 
superiority of early mastication, the use of hard and 
resisting food, and the general exercise of the jaw 
muscles ... as compared with soft feeding and 
artificial cleansing. "ii — and the above statement is 
more indisputable to-day than it was when written 
some six years ago. It is most important that no 
artificial procedure should be advocated which will 
appear to countenance unphysiological procedures. 
It is not only dental caries that has to be considered, 
and even though we could devise a system of artificial 
cleansing of the teeth which could be relied upon to 
prevent caries it would do infinite harm should it 
induce people to continue using the unphysiological 
diet, which is the cause of so many diseases besides 
caries at the present day. As things stand, however, 
fortunately the only thoroughly reliable method of pre- 
venting dental caries is the natural or physiological 



62 ARTIFICIAL METHODS 

one. And on the other hand, what statistics we have 
seem to show but Httle rehance can be put on artificial 
procedures. Thus in the better-class schools where 
the toothbrush is at least sometimes used, there is no 
evidence that the teeth are better than in schools 
where the toothbrush is not liseds^ — indeed, it is noted 
that " the better the school the' worse the teeth. "29 
Men and boys, who use artificial methods less than 
women and girls, seem also to have less caries. Indeed, 
while having no doubt that artificial methods properly- 
practised do some good in preventing the disease, we 
m.ust admit that there is as yet no satisfactory statis- 
tical evidence to show that the artificial procedures — 
as commonly executed — prevent dental caries. 

It would appear that we should regard and advocate 
the brushing of the teeth rather in the light of a cos- 
metic than as of any particular value in preventing 
caries. This view has been expressed in a leading 
article in the British Journal of Dental Science, which 
says : — 

" We have all observed mouths free from caries 
where no efforts at ' oral hygiene ' have ever been made, 
and we are all familiar with mouths requiring constant 
dental attention, the owners of which are zealous 
in the use of the toothbrush and dentifrices. In fact, 
with respect to the toothbrush, we are of opinion 
that its use is more of a cosmetic than of a prophylactic 
nature, though we by no means condemn its use as a 
means to prevent caries. "^^ 

The only artificial procedures which have a marked 
and undoubtedly beneficial effect are the various 
dental operations commonly resorted to, which restore 
the teeth to functional activity, or remove the diseased 
conditions which prevent functional activity and 
consequently the normal self-cleansing processes. 



Chapteh VI 

ON THE MEANS OF DISSEMINATING 
KNOWLEDGE NECESSARY FOR THE 
PREVENTION OF DENTAL CARIES 

From what has already been said it is obvious that 
the cleansing power of true or effectual mastication 
is better almost beyond comparison than artificial 
cleaning. Efficient mastication not only keeps the 
teeth clean and free from injurious plaques of bacteria, 
but the gums are kept clean, healthy, firm and so finely 
applied to the necks of the teeth as almost to defy the 
lodgment of all appropriate kinds of foods. The 
peridental membrane and alveolar processes are kept 
strong and healthy, and no doubt the gingival organ 
is likewise benefited. The bones of the jaws also are 
stimulated in their development, and the teeth are 
more perfectly implanted and regular than when mas- 
tication has been insufficient, and artificial cleansing 
has been solely relied upon for their welfare. More- 
over, digestion and the general health are both directly 
and indirectly benefited. It is, therefore, the obvious 
duty of every dental practitioner to instil into his 
patients the value of efficient mastication, and to get 
them to understand that no amount of artificial cleansing 
will make up for the continual transgression of the 
dictates of physiology, and that this is doubly important 
with regard to growing children whose habits have yet 
to be formed. It is hardly necessary to say that the 
attempt to teach the art of vigorous mastication is 

63 



64 DISSEMINATING KNOWLEDGE 

perfectly futile unless the food is of such a consistency 
as will stimulate or require it. From Dr. Black's 
Phago-dynamometric records we observe that the 
vigour of mastication is and must he proportional to 
the consistency of the food consumed, if the food is 
masticated at all. Here, however, we are met with a 
difficulty, for if medical practitioners advocate soft 
food for children, as in actual practice they very 
generally do, and the dentist advocates its discon- 
tinuance, then the diffusion of the required knowledge 
is greatly impeded. As the general medical practi- 
tioner comes in contact with children at a much earher 
age than the dentist does, great havoc may be wrought 
in children's mouths and teeth before the advice of a 
dentist may even be thought of. It is, therefore, 
obvious that medical men must learn or be taught how 
the mouth may be most effectually kept clean. There 
are few indeed, who realize that the mouth is, or at 
least ought to be, much cleaner after a meal which 
really requires mastication than at any other time. 
The detergent effects of the foodstuffs have admittedly 
been overlooked. It is not so very long since the idea 
that a meal invariably left the mouth dirty was 
generally believed even by dentists, so that we can 
hardly expect the public to be converted at once to the 
idea that the meals themselves should be cleansing 
to the mouth and teeth. It is not too much to say that, 
notwithstanding its immense importance from the 
point of view of general health, the natural hygiene 
of the mouth has in the past to all intents and purposes 
been entirely overlooked. It is true that artificial 
cleansing of the mouth has been insisted on, but that 
some foods leave the mouth physiologically clean, 
while others leave it dirty, seems never in any text- 
book of dietetics to have been so much as mentioned. 
Foods which lodge about the teeth and do not clean 
the mouth, have been recommended without the 
slightest concern as to whether they kept the mouth, 
and indirectly the alimentary canal, free from chronic 



DISSEMNATING KNOWT^EDGE 65 

fermentation, so long as they were known to be easily 
digestible and to supply the requisite amount of 
proteid, carbohydrate, etc. In fact, the viewing of 
food from its nutritional and not its hygienic value is 
still a matter for serious regret among those who under- 
stand the value of oral and indirectly ahmentary 
hygiene. Thus in reviewing an important medical 
bookis recently published, the British Dental Journal 
said, " We are at the outset pained to find that wherever 
a dietary is given in detail in this work, as being 
specially adapted for school children, no thought 
apparently has been given to the fact that human 
teeth are primarily intended for mastication, and 
that upon the functional activity of the teeth depends 
the proper development of the jaws ; again, we would 
point out that a diet should be so arranged as to pro- 
vide a natural toothbrush, and not be composed of 
those very ingredients which on fermentation lead to 
the production of lactic acid and consequent decalci- 
fication of the dental enamel. "33 It is obvious that 
the first thing required for the diffusion of the requisite 
knowledge is to have it clearly taught in text-books 
for dentists and medical practitioners. We may 
say that as far as dental text-books are concerned this 
has just recently been done,^ and is further about to be 
done in a forthcoming text-book, 2 and from what we can 
gather, what is being done in England to-day will, 
in the course of time, be done in other countries. 
With regard to medical text-books, unfortunately, the 
importance of the subject has not yet been fuUy 
realized by all the writers. Some, however, have 
recognized the more modern teaching of dentists, 
and further have advocated an abandonment of the 
current practice of pap feeding for children,^ not only 
on account of the teeth, but because of harmfulness 
with regard to the alimentary canalse and body 
generally.38 Notwithstanding this, however, it would 
seem desirable that more attention should be paid 
to the hygiene of the mouth by medical practitioners. 



66 DISSEMINATING KNOWLEDGE 

and only good would result from requiring from 
medical students an elementary knowledge of the 
principles of oral hygiene. Moreover, fuller recognition 
of dentistry as a branch of medicine at the universities 
where medical degrees are granted should be demanded. 
All this is important because the subject of oral hygiene 
is necessarily associated with questions of dietetics, 
and consequently in this matter it is to the medical 
profession that the public look largely for guidance. 
As regards the dental branch of the profession, it has 
been and is doing excellent work so far as that is possible 
under existing circumstances. The British Dental 
Association and the School Dentists Society, have 
made statistical investigations which have done much 
to awaken both the medical profession and the public 
to the great importance of the subject. Here it is 
hardly necessary to say that the treatment of school 
children's teeth should always be accompanied by 
instructions as to the prevention of the disease which 
will be effectual. Otherwise the chronic irritation 
of increasing rates, and the almost certain recurrence 
of the disease within a few years will most assuredly 
give rise to the suggestion that such treatment is not 
initiated by the highest motives. This would be 
a great misfortune, because the treatment of school 
children's teeth is itself of importance in preventing 
further caries. It makes the children able to eat food 
suitable for the hygiene of the mouth and alimentary 
canal, together with all its concomitant and conse- 
quent advantages. From what we have just said it 
may be observed that the best means of educating 
the public is through what may be called the recognized 
channels ; that is to say, those with special knowledge 
must expound the subject in such a way that the 
leaders of medical thought and writers of text-books 
shall become acquainted with the truths, and when 
this is done there is but little fear but that the truths 
will gradually become generally known. The public 
have always looked to the medical profession for 



DISSEMNATING KNOWLEDGE 67 

guidance, and there is no higher authority to whom 
they are able to appeal, and therefore no efforts should 
be relaxed, either in regard to perfecting the knowledge 
of the medical practitioner in this special branch of 
learning, or in bringing before his notice the reasons 
for considering the hygiene of the mouth as the most 
important part of preventive medicine. 



BIBLIOGRAPHY* 

1 . Badcock, J. H. — ^The Need for the Correction of the Malpositions 

of the Teeth. British Medical Journal, Sep. 17th, 19 10, p. 772, 

2. Bennett, N.G. — A System of Dental Surgery. Section, Etiol- 

ogy of Dental caries, by J. Sim Wallace. 

3. Black, G. V.t — Operative Dentistry. Vol. I., p. 165. 

4. Black, G. V. — Report of the Committee on Scientific Research. 

Dental Cosmos, 1908, p. 1424. 

5. Black, G. V. — ^The Physical Characters of the Teeth. Dental 

Cosmos, 1895, P- S^7> etc. 

6. Black, G. V. — Susceptibility and Immunity to Dental Caries. 

Sept., 1899, p. 829. 

7. Bogue, E. A. — Infant Diet a Factor in Dental Irregularities 

and Decay. Journal of the Allied Sciences. March, 191 o. 

8. Cam.pbeU, H. — Observations on Mastication. Lancet, July 

nth, i8th, 25th, and Aug. 8th, 1903. 

9. Colyer, J. F. — Dental Surgery and Pathology. Section (i) 

Etiology of Caries, pp. 606-612, and (2) Prophylaxis, p. 617 ; 
{3) Chronic General Periodontitis, p. 624. 

9a. Colyer, J. F. — Proc. Royal Soc. Med., Odonto. Section, Nov. 
23rd, 1908, p. 9 (Adenoids and the feeding of infants in 
relation to the growth of the jaws). 

10. Colyer, J. F. — Recent Views of Heredity. Dental Record, 

Jan., 1908, p. I. 

11. Dental Annual, 1904, p. 55. 

12. De Schweinitz and Randall. — Diseases of the Eye, Ear, Nose 

and Throat, Vol. 11. , p. 947 and p. 939. 

13. Editorial. British Journal of Dental Science. Nov. ist., 1905. 

14. Goadby, K. W. — The Buccal Secretions and Dental Caries. 

British Medical Journal, Sept. 17th, 19 10, p. 770. 

♦Quotations from the essayist's own writings are not notified. 

t The investigations of the late Dr. W. D. Miller with regard to 
the micro-organisms of the mouth and correlated subjects, together 
with Dr. G. V. Black's bacteriological, gnathodynamometric and 
chemical and physical investigations, are of quite exceptional 
importance in having provided data for the elucidation of the 
causation and prevention of dental caries. 

68 



BIBLIOGRAPHY 69 

15. Goadby, K. W. — ?kIycology of the Mouth, p. go. 

16. Hutchinson, R. — Food and the Principles of Dietetics, p. 205. 

17. Head J. — Miller's Obervations on the Wasting of Tooth Tissue. 

Dental Cosmos, 1907, p. 807. 

18. Kel>Tiack, T. N. — Medical Inspection of Schools and Scholars. 

19. Leading Article, British Journal of Dental Science, Nov. ist, 

1905 

20. Leading Article, Lancet, Oct. 21st, 1905. 

21. Mackenzie, Dan. — The Relations of Dentistry and OtolarjTi- 

gology. Dental Record, Dec, 1907. 

22. Miller, W. D. — Study of Immunity to the Diseases of the 

Mouth and Teeth, Dental Cosmos, Feb., 1903, p. 85. 

23. Miller, W. D. — ]Micro-organisms of the Human Mouth, p. 44. 

23a, p. 72. 23b, p. 208. 

24. Miller, W. D. — Study of Certain Questions Relating to the 

Pathology of the Teeth. Dental Cosmos, Dec, 1904, p. 983. 

25. Miller, W. D. — Study of Certain Questions Relating to the 

Pathology of the Teeth. Dental Cosmos, Jan., 1905, pp. 18 
and 23. 

26. Mouth Disinfection. Lancet, Nov. 20th, 1909, p. 15 12. 

27. Mouth Washes. British Medical Journal, Oct. 30th, 1909, 

p. 1300. 

28. Mummery, Stanley P. — Heredity and Dental Diseases. Pro- 

ceedings of the Royal Society of Medicine. Odontological 
Section, 1908, p. 108. 

29. Oliver, Sir Thomas. — Address to the Section of Industrial 

and School Hygiene. Journal of the Royal Institute of 
Public Health, 1910, p. 645. 

30. Peters, E. A. — Kel^iiack's Tuberculosis in Infancy and Child- 

hood, pp. 62 and 63. 

31. Paulow and Thompson. — The Work of the Digestive Glands. 

pp. 151-152. 

32. Pedley, R. D.— The Hygiene of the Mouth, p. 18. 

33. Review of Books. British Dental Journal, Sept. ist, 1910, 

p. 863. 

34. Schutzenberger. — Fermentation, p. 292. 

35. Spokes, Sydney. — Notes on Hypoplasia of the Enamel. 

Journal of the British Dental Association, 1897, p. 31. 

36. Sutherland, G. A. — Treatment of Children's Diseases p. no; 

36a, p. 13. 

37. Tomes, J. & C. S, — A System of Dental Surger^^ p. 16. 

38. Variot, G. et Lassabliere, P. — Troubles nutritifs produits par 

la panade dans les jeunes organismes. Comptes Rendus, 
Soc. Biologie, 10 juillet, 1908. 



70 BIBLIOGRAPHY 

39, Wallace, J. Sim, — The Addendum Prandii and Professional 

Education. British Dental Journal, Oct. ist. 1909. 

40, Wallace, J. Sim. — Oral Bacteria and Acquired Immunity. 

Medical Press and Circular, 1910, p. 424. 

41, Wallace, J. Sim. — Open Windows and Adenoids. Medical 

Press and Circular, 1908, p. 17 t,, 

426 Wallace, J. Sim. — Experiments and Observations on Bread. 
Proceedings of the Royal Society of Medicine, June, 191 1. 

43. Wallace, J. Sim. — The Irregularities of the Teeth. 43a, p. 79; 

44. Wallace, J. Sim. — ^The Cause and Prevention of Decay in 

Teeth, p. 7. 

45. Wallace, J. Sim. — Supplementary Essays on Dental Caries, 

Caps. II., III., IV. C. p. 77. 

46. Wallace, J. Sim. — The Role of Modern Dietetics in the Causa- 

tion of Disease. 

47. Wallace, J. Sim. — Transactions of the British Society for the 

Study of Orthodontics, Vol. I. 



APPENDIX 



Foodstuffs and Dental Caries 



NOT CLEANSING AND 
LIABLE TO INDUCE 
DENTAL CARIES. 

Farinaceous and 
sugary food in general 
without fibrous element. 

Examples : Sweet bis- 
cuits and cake ; bread 
and marmalade ; bread 
and jam ; new bread 
without crust; bread 
soaked in milk ; milk 
puddings ; porridge and 
milk ; preserved fruit ; 
chocolate and sweets of 
all kinds; honey. 

Liquids : Cocoa and 
chocolate. 

The above foods 
should not he eaten 
except when followed by 
foods of the cleansing 
kind. 



CLEANSING AND PRE- 
VENTIVE OF DENTAL 

CARIES. 

Fibrous foods generally. 

Examples : Fish, meat, 
bacon, poultry. Uncook- 
ed vegetables, lettuce, 
cress, radish, celery. 
Cooked vegetables are 
as a rule cleansing, but 
in a less degree than 
uncooked vegetables. 

Stale bread with crust ; 
toasted bread of all 
kinds; twice baked bread; 
pulled bread and cheese. 
Savouries. Fresh fruits, 
especially those requiring 
mastication, e.g., apples. 
Fatty foods, e.g., butter 
and margerine. Liquids : 
Tea, coffee, water, also 
soups and beef tea. 



Works by J. Sim Wallace, d.Sc, m.d.. l.d.s. 



"The Cause and Prevention of Decay in Teeth." 

2nd Edition. 1902. Price 5s. 

" We believe the conclusions are fair, and the day is not far distant 
when the dental world will come to believe them as he believes 
them," — Dental Headlight, U.S.A. 

" Mr. Wallace ably champions his own views, and the work has 
many points to stimulate thought." — Dental Record. 

" If not absolutely convincing, is none the less of great importance 
in calling attention to the dental dangers arising from our civilized 
methods of preparing food." — Journal of the British Dental Associa- 
tion. 

SUPPLEMENTARY ESSAYS ON 

" The Cause and Preventioa of Dental Caries." 

igo6. Price 2s. 6d. 

" The main contentions which have been made now for some years 
by the writer have been corroborated by laboratory tests. The 
question of food selection is treated with a broad outlook, and is one 
of the most interesting problems considered." — Medical Record. 

" Dr. Wallace argues his point well and his conclusions, though 
evidently not those of the dental world in general, seem thoroughly 
plausible. ' ' — Practitioner. 

" The R31e of Modem Dietetics in the Causation of Disease." 

1905. Price 3s. 6d. nett. 

" We agree that there should be a return to a more natural plan 
in the feeding of children." — British Medical Journal. 

" There has been a dearth of new publications during the year 
and of those issued perhaps the most suggestive and valuable has 
been Dr. J. Sim Wallace's book on ' Modern Dietetics in the Causa- 
tion of Disease.' " — Lancet {Annus Medicus). 

" Most suggestive and eminently practical." — Medical Press. 

" An uncompromising attack upon our choice of food, especially 

that for children The author's views are well worthy of 

careful consideration." — Edinburgh Medical Journal. 

" The Irregularities of the Teeth." 

1904 Price 5s. nett. 

" He also takes occasion to emphasize his well-known theory on 
the prevention of irregularity. Dr. Wallace writes very convinc- 
ingly on this topic and his conclusions are well worth studying." — 
The Dental Review. 

" Adenoids, irregularities and caries of the teeth and ' indigestion,' 
are so common that we are apt to accept them as a matter of course ; 
but when one realizes the amount of suffering and of financial loss 
that they entail on the community, one recognizes the urgent 
necessity of finding a means of prevention, and it is because we 
believe that Dr. Wallace has pointed out the means of very largely, 
if not entirely, preventing these evils, that we heartily commend 
the book to the attention of the profession." — Scottish Medical 
Journal.